View Poll Results: How much oil does your 2AZ-FE consume?
Voters: 63. You may not vote on this poll
Oil consumption
02-12-2012 | 08:14 AM
#41
Thread Starter
Joined: Jun 2007
Posts: 3,387
From: Baltimore, MD, USA
not quite true when my mechanic sees it on 80% of the 2.4l blocks he actually opens up, which has been at least hundreds, that 2.4 has been out for quite a while. dirt and what not can cause it, but it is also a known problem on the 2.4L They are minor meaning you will not have major problems if even minor. However vertical scratches can cause you to burn oil as the oil goes past the seal, through the scratch.
Out of curiousity, how deep were your scratches? Did you have to bore your liners over-size or simply re-hone them?
02-13-2012 | 01:13 PM
#43
Senior Member
SL Member
Joined: Jul 2008
Posts: 707
Well, another update for those who are interested. My car's got 50000 miles, and I've always used Pennzoil Platinum 5W-20 and I haven't consumed ANY oil yet and it's been 5000 miles already. Now, there are some who say this oil is terrible, but back on certain forums that I used to go to that were very tech-centric (which is the opposite of this forum, where everyone just throws around brand preferences and BS), oil analysis results say that this is the best oil of the proper weight you can get unless you go to Amsoil and Redline, which are true synthetic oils. I'd include German Castrol (yes, GERMAN castrol, not the normal stuff you see here) but I believe they only sell it here at 10W-30 or 10W-40.....too high for the typical 2AZFE engine, even if it is turbo IMO.
Once again, I really don't know why my engine is running so well...or if it's because 50000 miles isn't enough to be affected by this. But I'm also not running into the water pump problem that everyone also complains about....and it hasn't been replaced yet. Maybe I'm just lucky.
Once again, I really don't know why my engine is running so well...or if it's because 50000 miles isn't enough to be affected by this. But I'm also not running into the water pump problem that everyone also complains about....and it hasn't been replaced yet. Maybe I'm just lucky.
02-14-2012 | 02:08 AM
#44
Well, another update for those who are interested. My car's got 50000 miles, and I've always used Pennzoil Platinum 5W-20 and I haven't consumed ANY oil yet and it's been 5000 miles already.
<snip>
Once again, I really don't know why my engine is running so well...or if it's because 50000 miles isn't enough to be affected by this. But I'm also not running into the water pump problem that everyone also complains about....and it hasn't been replaced yet. Maybe I'm just lucky.
<snip>
Once again, I really don't know why my engine is running so well...or if it's because 50000 miles isn't enough to be affected by this. But I'm also not running into the water pump problem that everyone also complains about....and it hasn't been replaced yet. Maybe I'm just lucky.
), but I'm very happy with Pennzoil Syncromesh in my Eclipse transaxle, perhaps I should check out their Platinum 5W-20 at my next xB2 oil change 
!PS. I think "But I'm also not running into the water pump problem that everyone also complains about" is a slight exaggeration
!
02-14-2012 | 07:36 AM
#45
Thread Starter
Joined: Jun 2007
Posts: 3,387
From: Baltimore, MD, USA
Well, another update for those who are interested. My car's got 50000 miles, and I've always used Pennzoil Platinum 5W-20 and I haven't consumed ANY oil yet and it's been 5000 miles already. Now, there are some who say this oil is terrible, but back on certain forums that I used to go to that were very tech-centric (which is the opposite of this forum, where everyone just throws around brand preferences and BS), oil analysis results say that this is the best oil of the proper weight you can get unless you go to Amsoil and Redline, which are true synthetic oils. I'd include German Castrol (yes, GERMAN castrol, not the normal stuff you see here) but I believe they only sell it here at 10W-30 or 10W-40.....too high for the typical 2AZFE engine, even if it is turbo IMO.
It sounds like I'm not the only guy here who has spent some time at BITOG.
I agree 100% about Pennzoil Platinum (and Ultra), Amsoil and Redline (notice the omission of Royal Purple) as well as the German Castrol (US Castrol is mostly type 3 mineral oil base) and I'd add M1 to the list of top tier motor oils despite some claims of higher valvetrain wear. I do however disagree that 10w30 and 10w40 are too heavy for our 2AZFE. That really depends upon the temp range where you live and drive. Don from Dezod Motorsports (ASE Master Mech.) was kind enough to provide engine tolerance spec's for the 2AZFE and an older Subaru H4 turbo engine that called for 20w50. The tolerances were almost identical and Don recommends 10w40 for turbocharged 2AZFEs which is Dezod's specialty. I personally prefer 5w30 when the temp goes below 30F but wouldn't hesitate to run a good syn 10w30 or 10w40 above 30F.
Once again, I really don't know why my engine is running so well...or if it's because 50000 miles isn't enough to be affected by this. But I'm also not running into the water pump problem that everyone also complains about....and it hasn't been replaced yet. Maybe I'm just lucky.
IMO you, I and others burning less than 1qt every 5000 miles represent the norm while the majority of those posting in threads such as this represent a small minority who for whatever reason are experiencing higher than normal oil consumption. We all know that a disatisfied owner of anything is 100 times more likely to post on the www about it than the satisfied owner.
OTOH, maybe we are just lucky... but I doubt it.
02-14-2012 | 08:09 AM
#46
Senior Member
SL Member
Joined: Jun 2011
Posts: 140
Well... by the time your mechanic has to open up a 2AZ it obviously has serious problems and probably a lot of miles, poor maintenance or abuse. If not dirt, debris, over-heating or oil starvation, what else could cause those scratches? There are so many variables here that it's hard to say what exactly is causing a small percentage of 2AZ engines to burn oil excessively. Of those your mechanic has seen, I wonder how many are pre-piston oil squirters and post. In 07 or 08 Toyota added additional oil squirters below each piston to spray oil on the piston under-side to keep them cooler and I would imagine this also results in better cylinder wall oiling. In the case of those engines with cyl wall stratches, there are a multitude of possible causes including poor maintenance. A co-worker of mine with the mentality of the average Toyota owner (A-B appliance on wheels) recently had to replace his engine because he thought that the dash oil light was a low oil indicator and since it never came on, he never checked his oil level. When the idiot light finally did come on, he thought it could wait a few days...
Out of curiousity, how deep were your scratches? Did you have to bore your liners over-size or simply re-hone them?
Out of curiousity, how deep were your scratches? Did you have to bore your liners over-size or simply re-hone them?
02-14-2012 | 01:40 PM
#47
Senior Member
SL Member
Joined: Jul 2008
Posts: 707
It sounds like I'm not the only guy here who has spent some time at BITOG. I agree 100% about Pennzoil Platinum (and Ultra), Amsoil and Redline (notice the omission of Royal Purple) as well as the German Castrol (US Castrol is mostly type 3 mineral oil base) and I'd add M1 to the list of top tier motor oils despite some claims of higher valvetrain wear. I do however disagree that 10w30 and 10w40 are too heavy for our 2AZFE. That really depends upon the temp range where you live and drive. Don from Dezod Motorsports (ASE Master Mech.) was kind enough to provide engine tolerance spec's for the 2AZFE and an older Subaru H4 turbo engine that called for 20w50. The tolerances were almost identical and Don recommends 10w40 for turbocharged 2AZFEs which is Dezod's specialty. I personally prefer 5w30 when the temp goes below 30F but wouldn't hesitate to run a good syn 10w30 or 10w40 above 30F.
I agree 100% about Pennzoil Platinum (and Ultra), Amsoil and Redline (notice the omission of Royal Purple) as well as the German Castrol (US Castrol is mostly type 3 mineral oil base) and I'd add M1 to the list of top tier motor oils despite some claims of higher valvetrain wear. I do however disagree that 10w30 and 10w40 are too heavy for our 2AZFE. That really depends upon the temp range where you live and drive. Don from Dezod Motorsports (ASE Master Mech.) was kind enough to provide engine tolerance spec's for the 2AZFE and an older Subaru H4 turbo engine that called for 20w50. The tolerances were almost identical and Don recommends 10w40 for turbocharged 2AZFEs which is Dezod's specialty. I personally prefer 5w30 when the temp goes below 30F but wouldn't hesitate to run a good syn 10w30 or 10w40 above 30F.Also, when I said 10w-30 and 10w-40 are too heavy for our 2AZFE, you'll notice I said a TYPICAL 2AZFE....which is the non turbo type that is barely modified at all. Of course, oil weight is important when in certain temperature ranges, but I also made the assumption that most people don't have wild turbo setups. I've got nothing against super heavy weight oil, because even between oil companies the specs are different, but it needs to be for the proper application. Just trying to clear things up, because you missed the "typical" part
IMO you, I and others burning less than 1qt every 5000 miles represent the norm while the majority of those posting in threads such as this represent a small minority who for whatever reason are experiencing higher than normal oil consumption. We all know that a disatisfied owner of anything is 100 times more likely to post on the www about it than the satisfied owner.
OTOH, maybe we are just lucky... but I doubt it.
OTOH, maybe we are just lucky... but I doubt it.
Also, about the water pump thing, I wasn't trying to insult other people. I was just stating that there are a lot of people saying that they need to replace it, and maybe some of the types of posts that I see seem to amplify the effect. (IE: one guy going "omg I can't believe I have to replace my water pump every 30k miles!")
02-15-2012 | 08:50 AM
#48
Thread Starter
Joined: Jun 2007
Posts: 3,387
From: Baltimore, MD, USA
Thats just a horrible story you said at the end lmao =( He opens them up quite often to replace rod bearings. Our Stock rod bearings are not the best in the world, and that is the cause of the slight scratches in the side walls. Like i said they are minor if you have any at all. Got the turbo in now, just breaking everything in, need to put another 60 miles on it before i can change out the oil and start getting on it a little more.
Looking forward to more info/pics of your build.
02-15-2012 | 09:13 AM
#49
Thread Starter
Joined: Jun 2007
Posts: 3,387
From: Baltimore, MD, USA
Well, not only do I frequent BITOG, but also in SupraMania (I still do have a Supra though..) which happens to be a very tech-centric forum that frowns upon blind claims, especially in tech sections over there.
Also, when I said 10w-30 and 10w-40 are too heavy for our 2AZFE, you'll notice I said a TYPICAL 2AZFE....which is the non turbo type that is barely modified at all. Of course, oil weight is important when in certain temperature ranges, but I also made the assumption that most people don't have wild turbo setups. I've got nothing against super heavy weight oil, because even between oil companies the specs are different, but it needs to be for the proper application. Just trying to clear things up, because you missed the "typical" part
Also, when I said 10w-30 and 10w-40 are too heavy for our 2AZFE, you'll notice I said a TYPICAL 2AZFE....which is the non turbo type that is barely modified at all. Of course, oil weight is important when in certain temperature ranges, but I also made the assumption that most people don't have wild turbo setups. I've got nothing against super heavy weight oil, because even between oil companies the specs are different, but it needs to be for the proper application. Just trying to clear things up, because you missed the "typical" part
Sorry I wasn't more clear. What I meant was that (IMO) full-syn 10w30 or 10w40 would be great choices for a TYPICAL 2AZFE as long as the ambient temp remained above 30F. IMO just because a stock 2AZFE can tolerate thin 0/5w20 oil for at least the manufacturer's warranty period doesn't make it the best choice for anything other than fuel economy. JMO, I could be wrong...
Yes, dis-satisfied people always tend to make things public/vocal, so I agree with you.
Also, about the water pump thing, I wasn't trying to insult other people. I was just stating that there are a lot of people saying that they need to replace it, and maybe some of the types of posts that I see seem to amplify the effect. (IE: one guy going "omg I can't believe I have to replace my water pump every 30k miles!")
Also, about the water pump thing, I wasn't trying to insult other people. I was just stating that there are a lot of people saying that they need to replace it, and maybe some of the types of posts that I see seem to amplify the effect. (IE: one guy going "omg I can't believe I have to replace my water pump every 30k miles!")
I agree about the WP issue. Some of those people sound like litigants signing up for a class action for fictional SUI after they ran over or hit something by flooring the "brake" pedal...
02-15-2012 | 01:16 PM
#50
Senior Member
SL Member
Joined: Jul 2008
Posts: 707
Sorry I wasn't more clear. What I meant was that (IMO) full-syn 10w30 or 10w40 would be great choices for a TYPICAL 2AZFE as long as the ambient temp remained above 30F. IMO just because a stock 2AZFE can tolerate thin 0/5w20 oil for at least the manufacturer's warranty period doesn't make it the best choice for anything other than fuel economy. JMO, I could be wrong...
Well, right now I'm on Pennzoil Platinum 5W-20, which is a Group III Oil, which is basically close to Synthetic, but really isn't. Many other oils (including Mobil 1) are not true synthetic oils. People won't believe this but it's Exxon's way (and other companies) of making extra money. I'm not saying Mobil 1 is no good, but it just isn't true synthetic. My plan for next oil change is to switch to a true synthetic, like Amsoil (Group IV)/Redline (Group V). Probably Amsoil 0W-20 since it's getting a little cold here....or 5W-20 just cause that's what I've been running for most of the car's life. Not sure if I should go for an extended OIC because the car may EVENTUALLY start to consume my precious oil, lol.
02-15-2012 | 08:07 PM
#51
Thread Starter
Joined: Jun 2007
Posts: 3,387
From: Baltimore, MD, USA
I'm not sure why you would want the "cold weight" to be so high on a car that is barely modified, even if the ambient temperatures are high. Then there is also the influence that I live in a place that experiences all four seasons and would never run a weight like that anyway. I think for the people with oil consumption issues should stick with 0W-30 or 5W-30. I really don't see an advantage of 10W-Anything if you're barely modified.
I'm sure that I'm over-simplifying things here but my limited understanding is that the cold weight represents the viscosity of the base oil stock. Polymers are then added to make the oil behave like a heavier weight when hot. When polymers break down they can create sludge and if left to break down completely the remaining oil would be equivalent to the base stock viscosity. My understanding is that, whenever possible, it's best to choose an oil with the least viscosity range for the anticipated temp range in which it will be used. E.g., 10w30 or 10w40 in summer and 0w30 or 5w30 in winter (*w20 for increased fuel economy). That is why, (right or wrong) that I would avoid 0w30/40 as well as the fact that it never gets cold enough in MD or PA to require a 0w oil.
FYI:
The pour point for M1 10w40 is -33C, 10w30 is -37C and 5w30 is -39C and 5w20 is -43C. Mobil does not provide pour point data for their 0w* oils but IIRC I saw a figure of -50C elsewhere (no link).
Well, right now I'm on Pennzoil Platinum 5W-20, which is a Group III Oil, which is basically close to Synthetic, but really isn't. Many other oils (including Mobil 1) are not true synthetic oils. People won't believe this but it's Exxon's way (and other companies) of making extra money. I'm not saying Mobil 1 is no good, but it just isn't true synthetic. My plan for next oil change is to switch to a true synthetic, like Amsoil (Group IV)/Redline (Group V). Probably Amsoil 0W-20 since it's getting a little cold here....or 5W-20 just cause that's what I've been running for most of the car's life. Not sure if I should go for an extended OIC because the car may EVENTUALLY start to consume my precious oil, lol.
In the end all we can do is educate ourselves with the limited info available to us and make our best guesses. I can't say whether my guesses are more accurate than yours or anyone elses but it can be informative to share our subject knowledge and opinions. Please feel free to correct me on anything I've stated above. I do not wish to present my opinions as fact.
02-16-2012 | 01:54 AM
#52
Senior Member
SL Member
Joined: Jul 2008
Posts: 707
Here's a useful article from good old Dr. Haas
Yes, I read this awhile ago, and realized I was incorrect when I stated that ambient temperature actually mattered...my mistake. But anyways, there's the article.
Cliff notes: 0W-Whatever is usually preferred over XW-Whatever, assuming X > 0.
Chapter One - Motor Oil 101
I think it is time to go over passenger car automotive engine oils in detail. I will be writing several articles to be published soon so I will try to get some of it out here. I feel this is a very general topic for all car owners on this board.
This is a very difficult topic to comprehend. Everybody including good mechanics think they are experts in this field but few understand engine oils. Most of what I hear is the opposite of the truth. It is however easy to see how people get mixed up as there is always some truth to the misconception.
Please forgive me if I am too wordy or even verbose at times. I will be redundant for certain. This will be in areas that people have to hear things over and over again to get it right. Some will never be able to understand these concepts unfortunately. I base my thoughts on those whom I have been listening to in various automotive chat rooms and discussion with mechanics. I will try to minimize technical terms and be somewhat vague rather than exact. I will round and average numbers to make the point simple rather than mathematically exact. Thickness has the same meaning as viscosity. Viscosity is a measure of the resistance of a fluid (liquid or gas) to flow. Fluids with high viscosity, such as molasses, flow more slowly than those with low viscosity, such as water. Again, I am trying to explain general principals as I know them.
The greatest confusion is because of the way motor oils are labeled. It is an old system and is confusing to many people. I know the person is confused when they say that a 0W-30 oil is too thin for their engine because the old manual says to use 10W-30. This is wrong.
More confusion occurs because people think in terms of the oil thinning when it gets hot. They think this thinning with heat is the problem with motor oil. It would be more correct to think that oil thickens when it cools to room temperature and THIS is the problem. In fact this is the problem. It is said that 90 percent of engine wear occurs at startup. If we are interested in engine longevity then we should concentrate our attention at reducing engine wear at startup.
Oils are chosen by the manufacturer to give the right thickness at the normal operating temperature of the engine. I will say this average oil temperature is 212 F, the boiling point of water. On the track that temperature is up to 302F. It is important to realize that these are two different operating environments and require different oils.
I will discuss driving around town first. Everything I say will be based on these conditions. At a later time I will discuss track conditions. Everything I say will be as accurate as possible without looking everything up and footnoting. I am trying to be general not ultra specific.
One thing that is no longer important is the ambient temperature. Older automotive owner manuals often recommended one oil for the summer and another for the winter. This is still necessary for air cooled engines but is no longer a consideration in pressurized water cooled engines. These engine blocks are kept at around 212 F all year round. The oil is around the same temperature as well. This allows for a single weight oil all year round. Again, this is not the same as on the track where the coolant temperature is slightly higher and the oil temperature is much higher.
Please forget those numbers on the oil can. They really should be letters as AW-M, BW-N or CW-P. The fact that we are dealing with a system of numbers on the can makes people think that they represent the viscosity of the oil inside the can. The problem is that the viscosity of oil varies with its temperature. A “30” weight oil has a viscosity of 3 at 302 F ( 150 C ) and thickens to 10 at 212 F ( 100 C ). It further thickens to a viscosity of 100 at 104 F ( 40 C ) and is too thick to measure at the freezing point of 32 F ( 0 C ).
30 weight oil:
Temperature ( F )....Thickness
302...........................3
212..........................10
104..........................100
32..........................250 (rough estimate)
The automotive designers usually call for their engines to run at 212 F oil and water temperature with an oil thickness of 10. This is the viscosity of the oil, not the weight as labeled on the oil can. I want to stay away from those numbers as they are confusing. We are talking about oil thickness, not oil can labeling. This will be discussed later. Forget the numbers on that oil can for now. We are only discussing the thickness of the oil that the engine requires during normal operating conditions.
The engine is designed to run at 212 F at all external temperatures from Alaska to Florida. You can get in your car in Florida in September and drive zig-zag to Alaska arriving in November. The best thing for your engine would be that it was never turned off, you simply kept driving day and night. The oil thickness would be uniform, it would always be 10. In a perfect world the oil thickness would be 10 at all times and all temperatures.
If the thickness of oil was 10 when you got in your car in the morning and 10 while driving it would be perfect. You would not have to warm up your engine. You could just get in the car and step on the gas. There would be little wear and tear on you engine, almost none. Unfortunately the world is not perfect.
The night before when you drove home from work the car was up the the correct operating temperature and the oil was the correct thickness, 10. Over night the engine cooled to room temperature and the oil thickened. It is 75 F in the morning now (I do live in Florida). The oil thickness is now around 150. It is too thick to lubricate an engine designed to run with an oil having a thickness of 10.
It is time to introduce the concept of lubrication. Most believe that pressure = lubrication. This is false. Flow = lubrication. If pressure was the thing that somehow lubricated your engine then we would all be using 90 weight oil. Lubrication is used to separate moving parts, to keep them from touching. There is a one to one relationship between flow and separation. If you double the flow you will double the separation pressure in a bearing. The pressure at the bearing entrance is irrelevant.
In fact the relationship between pressure and flow is in opposition. If you change your oil to a thicker formula the pressure will go up. It goes up because the resistance to flow is greater and in fact the flow must go down in order for the pressure to go up. They are inversely related. Conversely if you choose a thinner oil then the pressure will go down. This can only occur if the flow has increased.
It seems then that we should all be using the thinnest oil money can buy. This is partly true. Let me use my 575 Ferrari Maranello as an example. I drive this car around town. The manual of this car states the target pressure is 75 PSI at 6,000 RPM. The gold standard is that all engines should have a pressure of 10 PSI for every 1,000 RPM of operation, not more, not less. After all, you do need some pressure to move that oil along, but only enough pressure, not more. More pressure is not better, it can only result from the impedance of oil flow. Remember that oil flow is the only thing that does the lubricating.
Note that Ferrari is not saying what thickness of oil to use. That can only be determined by experimentation. My engine oil temperature is running around 185 F as I drive around town on a hot Florida summer day. I have found that the thinnest oil I can buy that is API / SAE certified is Mobil 1’s thinnest oil. Even with this oil I get 80 PSI at 2,000 RPM. It is too thick for my application yet it is the thinnest oil money can buy. If I was on a hot Florida track in mid-summer the oil temperature would probably get up to 302 F. I will guess that the pressure would only be 40 PSI at 6,000 RPM. The oil I am using would not meet the requirement of 75 PSI at 6,000 RPM from Ferrari. I would have to choose a thicker oil for this racing situation. The oil I use now would be too thin at that very high temperature. (This is only partly true. Higher RPM running engines use thinner and thinner oils to get more and more flow. I will discuss this later).
High flow does more than lubricate. It is one of the things used to cool the hottest parts of your engine, the pistons, valve areas and bearings. This cooling effect is as important as lubrication in your engine. If your engine is running hot use a thinner oil. The flow will increase and so will the cooling. This is even more important in the racing condition.
Let us go back to the Ferrari manual. My older 550 Maranello only specified 5W-40 Shell Helix Ultra as the oil to use in all conditions. This car was designed for racing. As it turns out Ferrari now recognizes that not every owner races their cars. The newer 575 manual now states to use 0W-40 for around town situations even though Shell does not make this oil in the Helix Ultra formulation at this writing. They also recommend the 5W-40 by Shell if you insist on the Shell product. It is also the recommended oil for most racing conditions.
Ferrari recommends Helix Ultra Racing 10W-60 “for hot climate conditions racing type driving on tracks”. Note that they now realize the difference between the daily urban driver like me and the very different racing situation. These are widely different circumstances. I want to emphasize that they only want you to use this oil while racing in “hot climate conditions”. If you are racing in Watkins Glen up north use the 5W-40. If you are racing in Sebring in the middle of the Florida summer use the 10W-60. Around town in any climate, use the 0W-40.
It is time to dispel the notion that 0W-30 oil is too thin when our manual calls for 10W-30. A 0W-30 is always the better choice, always. The 0W-30 is not thinner. It is the same thickness as the 10W-30 at operating temperatures. The difference is when you turn your engine off for the night. Both oils thicken over the evening and night. They both had a thickness, a viscosity of 10 when you got home and turned your engine off. That was the perfect thickness for engine operation.
As cooling occurs and you wake up ready to go back to work the next day the oils have gotten too thick for your engine to lubricate properly. It is 75 F outside this morning. One oil thickened to a viscosity of say 90. The other thickened to a viscosity of 40. Both are too thick in the morning at startup. But 40 is better than 90. Your engine wants the oil to have a thickness of 10 to work properly. You are better off starting with the viscosity of 40 than the honey - like oil with a viscosity of 90.
I repeat: More confusion occurs because people think in terms of the oil thinning when it gets hot. They think this thinning with heat is the problem with motor oil. It would be more correct to think that oil thickens when it cools to room temperature and THIS is the problem. In fact this is the problem.
This is the end of lesson number one.
aehaas
About the author:
Dr. Haas is a physician and surgeon. He graduated from the University of Florida with a degree in biochemistry with honors. He studied motor oils since high school where he did independent studies on this topic. He studied the properties of viscosity.
When he was a general surgery resident in Chapel Hill he studied the flow mechanics of human blood. Today he continues his research by discussion of oil products with chemists in the field and chemists from the oil manufacturers.
He has personal racing experience in Formula Super Vee. He is his own Lamborghini and Ferrari as well as Mercedes mechanic.
I think it is time to go over passenger car automotive engine oils in detail. I will be writing several articles to be published soon so I will try to get some of it out here. I feel this is a very general topic for all car owners on this board.
This is a very difficult topic to comprehend. Everybody including good mechanics think they are experts in this field but few understand engine oils. Most of what I hear is the opposite of the truth. It is however easy to see how people get mixed up as there is always some truth to the misconception.
Please forgive me if I am too wordy or even verbose at times. I will be redundant for certain. This will be in areas that people have to hear things over and over again to get it right. Some will never be able to understand these concepts unfortunately. I base my thoughts on those whom I have been listening to in various automotive chat rooms and discussion with mechanics. I will try to minimize technical terms and be somewhat vague rather than exact. I will round and average numbers to make the point simple rather than mathematically exact. Thickness has the same meaning as viscosity. Viscosity is a measure of the resistance of a fluid (liquid or gas) to flow. Fluids with high viscosity, such as molasses, flow more slowly than those with low viscosity, such as water. Again, I am trying to explain general principals as I know them.
The greatest confusion is because of the way motor oils are labeled. It is an old system and is confusing to many people. I know the person is confused when they say that a 0W-30 oil is too thin for their engine because the old manual says to use 10W-30. This is wrong.
More confusion occurs because people think in terms of the oil thinning when it gets hot. They think this thinning with heat is the problem with motor oil. It would be more correct to think that oil thickens when it cools to room temperature and THIS is the problem. In fact this is the problem. It is said that 90 percent of engine wear occurs at startup. If we are interested in engine longevity then we should concentrate our attention at reducing engine wear at startup.
Oils are chosen by the manufacturer to give the right thickness at the normal operating temperature of the engine. I will say this average oil temperature is 212 F, the boiling point of water. On the track that temperature is up to 302F. It is important to realize that these are two different operating environments and require different oils.
I will discuss driving around town first. Everything I say will be based on these conditions. At a later time I will discuss track conditions. Everything I say will be as accurate as possible without looking everything up and footnoting. I am trying to be general not ultra specific.
One thing that is no longer important is the ambient temperature. Older automotive owner manuals often recommended one oil for the summer and another for the winter. This is still necessary for air cooled engines but is no longer a consideration in pressurized water cooled engines. These engine blocks are kept at around 212 F all year round. The oil is around the same temperature as well. This allows for a single weight oil all year round. Again, this is not the same as on the track where the coolant temperature is slightly higher and the oil temperature is much higher.
Please forget those numbers on the oil can. They really should be letters as AW-M, BW-N or CW-P. The fact that we are dealing with a system of numbers on the can makes people think that they represent the viscosity of the oil inside the can. The problem is that the viscosity of oil varies with its temperature. A “30” weight oil has a viscosity of 3 at 302 F ( 150 C ) and thickens to 10 at 212 F ( 100 C ). It further thickens to a viscosity of 100 at 104 F ( 40 C ) and is too thick to measure at the freezing point of 32 F ( 0 C ).
30 weight oil:
Temperature ( F )....Thickness
302...........................3
212..........................10
104..........................100
32..........................250 (rough estimate)
The automotive designers usually call for their engines to run at 212 F oil and water temperature with an oil thickness of 10. This is the viscosity of the oil, not the weight as labeled on the oil can. I want to stay away from those numbers as they are confusing. We are talking about oil thickness, not oil can labeling. This will be discussed later. Forget the numbers on that oil can for now. We are only discussing the thickness of the oil that the engine requires during normal operating conditions.
The engine is designed to run at 212 F at all external temperatures from Alaska to Florida. You can get in your car in Florida in September and drive zig-zag to Alaska arriving in November. The best thing for your engine would be that it was never turned off, you simply kept driving day and night. The oil thickness would be uniform, it would always be 10. In a perfect world the oil thickness would be 10 at all times and all temperatures.
If the thickness of oil was 10 when you got in your car in the morning and 10 while driving it would be perfect. You would not have to warm up your engine. You could just get in the car and step on the gas. There would be little wear and tear on you engine, almost none. Unfortunately the world is not perfect.
The night before when you drove home from work the car was up the the correct operating temperature and the oil was the correct thickness, 10. Over night the engine cooled to room temperature and the oil thickened. It is 75 F in the morning now (I do live in Florida). The oil thickness is now around 150. It is too thick to lubricate an engine designed to run with an oil having a thickness of 10.
It is time to introduce the concept of lubrication. Most believe that pressure = lubrication. This is false. Flow = lubrication. If pressure was the thing that somehow lubricated your engine then we would all be using 90 weight oil. Lubrication is used to separate moving parts, to keep them from touching. There is a one to one relationship between flow and separation. If you double the flow you will double the separation pressure in a bearing. The pressure at the bearing entrance is irrelevant.
In fact the relationship between pressure and flow is in opposition. If you change your oil to a thicker formula the pressure will go up. It goes up because the resistance to flow is greater and in fact the flow must go down in order for the pressure to go up. They are inversely related. Conversely if you choose a thinner oil then the pressure will go down. This can only occur if the flow has increased.
It seems then that we should all be using the thinnest oil money can buy. This is partly true. Let me use my 575 Ferrari Maranello as an example. I drive this car around town. The manual of this car states the target pressure is 75 PSI at 6,000 RPM. The gold standard is that all engines should have a pressure of 10 PSI for every 1,000 RPM of operation, not more, not less. After all, you do need some pressure to move that oil along, but only enough pressure, not more. More pressure is not better, it can only result from the impedance of oil flow. Remember that oil flow is the only thing that does the lubricating.
Note that Ferrari is not saying what thickness of oil to use. That can only be determined by experimentation. My engine oil temperature is running around 185 F as I drive around town on a hot Florida summer day. I have found that the thinnest oil I can buy that is API / SAE certified is Mobil 1’s thinnest oil. Even with this oil I get 80 PSI at 2,000 RPM. It is too thick for my application yet it is the thinnest oil money can buy. If I was on a hot Florida track in mid-summer the oil temperature would probably get up to 302 F. I will guess that the pressure would only be 40 PSI at 6,000 RPM. The oil I am using would not meet the requirement of 75 PSI at 6,000 RPM from Ferrari. I would have to choose a thicker oil for this racing situation. The oil I use now would be too thin at that very high temperature. (This is only partly true. Higher RPM running engines use thinner and thinner oils to get more and more flow. I will discuss this later).
High flow does more than lubricate. It is one of the things used to cool the hottest parts of your engine, the pistons, valve areas and bearings. This cooling effect is as important as lubrication in your engine. If your engine is running hot use a thinner oil. The flow will increase and so will the cooling. This is even more important in the racing condition.
Let us go back to the Ferrari manual. My older 550 Maranello only specified 5W-40 Shell Helix Ultra as the oil to use in all conditions. This car was designed for racing. As it turns out Ferrari now recognizes that not every owner races their cars. The newer 575 manual now states to use 0W-40 for around town situations even though Shell does not make this oil in the Helix Ultra formulation at this writing. They also recommend the 5W-40 by Shell if you insist on the Shell product. It is also the recommended oil for most racing conditions.
Ferrari recommends Helix Ultra Racing 10W-60 “for hot climate conditions racing type driving on tracks”. Note that they now realize the difference between the daily urban driver like me and the very different racing situation. These are widely different circumstances. I want to emphasize that they only want you to use this oil while racing in “hot climate conditions”. If you are racing in Watkins Glen up north use the 5W-40. If you are racing in Sebring in the middle of the Florida summer use the 10W-60. Around town in any climate, use the 0W-40.
It is time to dispel the notion that 0W-30 oil is too thin when our manual calls for 10W-30. A 0W-30 is always the better choice, always. The 0W-30 is not thinner. It is the same thickness as the 10W-30 at operating temperatures. The difference is when you turn your engine off for the night. Both oils thicken over the evening and night. They both had a thickness, a viscosity of 10 when you got home and turned your engine off. That was the perfect thickness for engine operation.
As cooling occurs and you wake up ready to go back to work the next day the oils have gotten too thick for your engine to lubricate properly. It is 75 F outside this morning. One oil thickened to a viscosity of say 90. The other thickened to a viscosity of 40. Both are too thick in the morning at startup. But 40 is better than 90. Your engine wants the oil to have a thickness of 10 to work properly. You are better off starting with the viscosity of 40 than the honey - like oil with a viscosity of 90.
I repeat: More confusion occurs because people think in terms of the oil thinning when it gets hot. They think this thinning with heat is the problem with motor oil. It would be more correct to think that oil thickens when it cools to room temperature and THIS is the problem. In fact this is the problem.
This is the end of lesson number one.
aehaas
About the author:
Dr. Haas is a physician and surgeon. He graduated from the University of Florida with a degree in biochemistry with honors. He studied motor oils since high school where he did independent studies on this topic. He studied the properties of viscosity.
When he was a general surgery resident in Chapel Hill he studied the flow mechanics of human blood. Today he continues his research by discussion of oil products with chemists in the field and chemists from the oil manufacturers.
He has personal racing experience in Formula Super Vee. He is his own Lamborghini and Ferrari as well as Mercedes mechanic.
Cliff notes: 0W-Whatever is usually preferred over XW-Whatever, assuming X > 0.
02-16-2012 | 02:58 AM
#53
Presuming he genuinely knows his motor oil stuff, hell of a good read. What he's saying is that first number is actually better at 0W (apparently related to the low temp viscosity)! So how about the second number? I'm suspecting 30 to 40 is more desirable than 20W.
Perhaps my running M1 10W30 "High Mileage" in my 130Kmi turbo Eclipse is a mistake?
Perhaps my running M1 10W30 "High Mileage" in my 130Kmi turbo Eclipse is a mistake?
02-16-2012 | 10:31 AM
#54
Thread Starter
Joined: Jun 2007
Posts: 3,387
From: Baltimore, MD, USA
To FromTheOld:
Good article and I enjoyed the re-read. All of my posted info/opinion also came from BITOG (or so I thought) but I can't seem to find the source now (still looking). I did however find a very interesting difference between mineral and PAO oils with regard to base oil viscosity. Apparently while a 5w30 mineral based oil (group 1/2/3) starts with 5w base oil, thickened with polymer addition, a 5w30 PAO (group 4/5) oil starts with 30w base oil. To me this is a key difference when choosing a PAO viscosity range vs mineral oil.
In light of this new and reminder info, I'd like to change my previous recommendation from 10w30/40 to 0w30/40. I still wouldn't use or recommend *w20 unless MPG was more important than engine longevity such as the case of a leased vehicle that will be returned within the powertrain warranty period.
Good article and I enjoyed the re-read. All of my posted info/opinion also came from BITOG (or so I thought) but I can't seem to find the source now (still looking). I did however find a very interesting difference between mineral and PAO oils with regard to base oil viscosity. Apparently while a 5w30 mineral based oil (group 1/2/3) starts with 5w base oil, thickened with polymer addition, a 5w30 PAO (group 4/5) oil starts with 30w base oil. To me this is a key difference when choosing a PAO viscosity range vs mineral oil.
In light of this new and reminder info, I'd like to change my previous recommendation from 10w30/40 to 0w30/40. I still wouldn't use or recommend *w20 unless MPG was more important than engine longevity such as the case of a leased vehicle that will be returned within the powertrain warranty period.
02-16-2012 | 12:12 PM
#55
Senior Member
SL Member
Joined: Jul 2008
Posts: 707
Presuming he genuinely knows his motor oil stuff, hell of a good read. What he's saying is that first number is actually better at 0W (apparently related to the low temp viscosity)! So how about the second number? I'm suspecting 30 to 40 is more desirable than 20W.
Perhaps my running M1 10W30 "High Mileage" in my 130Kmi turbo Eclipse is a mistake?
Perhaps my running M1 10W30 "High Mileage" in my 130Kmi turbo Eclipse is a mistake?
Yes, XW-XX notation states that anything before the "-" is the low temperature/cold viscosity, which is when the car has not been driven/ran for awhile. While anything after the "-" states the weight of the oil during operating temperatures (when being driven). The reason for lower weight on cold startup is stated in the article (with the #'s example. 10 being "ideal" while everything else being unideal)
I can't comment about your Eclipse. It really depends on its condition.....many many variables. Mind you, even though my Supra recommended 10W-30 in the manual, I never followed that because oil has come a LONG way from back then. I run German Castrol 0W-30 in my Supra and it's completely fine.
02-16-2012 | 12:16 PM
#56
Senior Member
SL Member
Joined: Jul 2008
Posts: 707
To FromTheOld:
Good article and I enjoyed the re-read. All of my posted info/opinion also came from BITOG (or so I thought) but I can't seem to find the source now (still looking). I did however find a very interesting difference between mineral and PAO oils with regard to base oil viscosity. Apparently while a 5w30 mineral based oil (group 1/2/3) starts with 5w base oil, thickened with polymer addition, a 5w30 PAO (group 4/5) oil starts with 30w base oil. To me this is a key difference when choosing a PAO viscosity range vs mineral oil.
Good article and I enjoyed the re-read. All of my posted info/opinion also came from BITOG (or so I thought) but I can't seem to find the source now (still looking). I did however find a very interesting difference between mineral and PAO oils with regard to base oil viscosity. Apparently while a 5w30 mineral based oil (group 1/2/3) starts with 5w base oil, thickened with polymer addition, a 5w30 PAO (group 4/5) oil starts with 30w base oil. To me this is a key difference when choosing a PAO viscosity range vs mineral oil.
In light of this new and reminder info, I'd like to change my previous recommendation from 10w30/40 to 0w30/40. I still wouldn't use or recommend *w20 unless MPG was more important than engine longevity such as the case of a leased vehicle that will be returned within the powertrain warranty period.
02-17-2012 | 12:15 AM
#57
Thread Starter
Joined: Jun 2007
Posts: 3,387
From: Baltimore, MD, USA
What kind of base stocks does AMSOIL use? Are AMSOIL synthetic lubricants PAO-based?
Answer: AMSOIL maintains formulation details as proprietary and does not divulge specifics regarding the type of synthetic base stocks used in its synthetic lubricants. AMSOIL developed the world’s first API-qualified synthetic motor oil in 1972 and has remained the leader in the synthetic lubricant industry by continually researching new technologies and demanding only the highest-quality raw materials. As the company moves forward with new technologies it is increasingly more important that this information remains proprietary. AMSOIL views synthetic base oils the same as it views additives, with each having its own set of unique properties. AMSOIL does not insist on a particular type of base stock, but insists on particular performance parameters. AMSOIL chooses whichever synthetic base stock or combination of base stocks delivers the desired result and tailors its lubricants to be application-specific (gasoline, diesel, racing, transmission, gear, extended drain, extreme temperatures, etc.). At the end of the day, the type of base stock used to formulate the oil is inconsequential; the product’s performance is what matters.
Well, XW-20 seems to run fine for me (but once again, I attribute this to luck?), and I occasionally drive aggressive, but I think 0W-30 is the safest bet for the general population
Xw20 is perfectly adequate for normal use and auto makers wouldn't recommend it if it wasn't. I didn't mean to imply that it was inadequate, just that (IMO) Xw30 provides better engine protection.
02-17-2012 | 01:14 AM
#58
He does know his stuff for sure. I was directed to that article by two mechanics in the air force who are very knowledgeable about cars and who also frequent BITOG.
Yes, XW-XX notation states that anything before the "-" is the low temperature/cold viscosity, which is when the car has not been driven/ran for awhile. While anything after the "-" states the weight of the oil during operating temperatures (when being driven). The reason for lower weight on cold startup is stated in the article (with the #'s example. 10 being "ideal" while everything else being unideal)
I can't comment about your Eclipse. It really depends on its condition.....many many variables. Mind you, even though my Supra recommended 10W-30 in the manual, I never followed that because oil has come a LONG way from back then. I run German Castrol 0W-30 in my Supra and it's completely fine.
Yes, XW-XX notation states that anything before the "-" is the low temperature/cold viscosity, which is when the car has not been driven/ran for awhile. While anything after the "-" states the weight of the oil during operating temperatures (when being driven). The reason for lower weight on cold startup is stated in the article (with the #'s example. 10 being "ideal" while everything else being unideal)
I can't comment about your Eclipse. It really depends on its condition.....many many variables. Mind you, even though my Supra recommended 10W-30 in the manual, I never followed that because oil has come a LONG way from back then. I run German Castrol 0W-30 in my Supra and it's completely fine.
! Starting a couple years ago, I cut my oil with a quart of MMO, and this discussion suggests it should definitely help the start up viscosity (recognizing additives like that are inherently controversial ). Guess I should consider a lower cold viscosity oil for my Eclipse, but seems odd Mobil specifically formulated their 10W-30 "High Mileage" for high mileage cars. That first number went up! Wonder what that's all about?
02-17-2012 | 02:24 AM
#59
Wow this thread is informative! Well I just voted on the poll that I burn 1qt every 2k miles, because on my last oil change I put in 4qts but only took out about 2-2.5qts. I have an 09 Tc with about 56k miles and change my oil every 5k miles. I'm actually doing the oil consumption test right now and hoping to burn enough oil to get new pistons.
02-17-2012 | 09:15 AM
#60
Thread Starter
Joined: Jun 2007
Posts: 3,387
From: Baltimore, MD, USA
Thanks ! Starting a couple years ago, I cut my oil with a quart of MMO, and this discussion suggests it should definitely help the start up viscosity (recognizing additives like that are inherently controversial ). Guess I should consider a lower cold viscosity oil for my Eclipse, but seems odd Mobil specifically formulated their 10W-30 "High Mileage" for high mileage cars. That first number went up! Wonder what that's all about?
! Starting a couple years ago, I cut my oil with a quart of MMO, and this discussion suggests it should definitely help the start up viscosity (recognizing additives like that are inherently controversial ). Guess I should consider a lower cold viscosity oil for my Eclipse, but seems odd Mobil specifically formulated their 10W-30 "High Mileage" for high mileage cars. That first number went up! Wonder what that's all about?I prefer to go by the manufacturer's product data sheet than the viscosity range on the label. I look for an oil with a Vis of >10 at 100C and <60 at 40C. FWIW, Audi, BMW, Porsche and VW all call for oil with a Vis of ~15 (w40) at 100C, most others specify a Vis of 10 (w30) at 100C while *w20 is rated at only Vis 8 at 100C. The higher the Vis at 100C, the better the engine protection at operating temps. While a full race engine might require an operating Vis of 20, a normal street-driven engine only needs a Vis of 10 and for the sake of improved fuel economy, many auto makers have decided that a Vis of 8 is enough.