Mobil 15w50 in 0w20 engine.

[DoubleWasp]

Originally Posted By: Gokhan

Originally Posted By: DoubleWasp

You haven't posted the data to support that. There's only two cars posted up.

I posted 30 cars in the last list. I can't post the entire CR Web site for obvious copyright reasons and wouldn't have time to do so anyway. However, all Lexus and Toyota cars are top-rated in reliability. Other Japanese cars also rate very well. Worst-rated cars are European cars. Subscribe to CR ($20 a year) and look at them if you are interested.

Your list includes Japanese cars running 0w-20.

 

[DoubleWasp]

Originally Posted By: Gokhan

Originally Posted By: Shannow

It's an improvement from plucking from the frectum per normal days

I post a couple of vague sentences on engine longevity when using three viscosity grades heavier than recommended for no good reason, and then insults start rushing in. Why would you elevate your oil temperature substantially by running three viscosity grades heavier? The worst thing that is happening on the seals, including valve-stem oil seals, is the oil temperature. Higher the temperature faster they will harden and fail. My main analysis was regarding loss of horsepower and fuel economy, not even longevity issues. It's plain silly to sacrifice horsepower and fuel economy using an oil much thicker than recommended for no good reason (no towing, no high loads, etc.). It's probably also borderline paranoid and/or masochistic. The only pro you can come up with is thicker oil film and perhaps a wider margin of protection against engine wear. I can come up with so many cons: Higher oil temperature Excessive oil pressure Reduced oil flow Increased engine temperature Too thick during warm-up Loss of horsepower Loss of MPG Higher stress on the oil filter and substantially increased frequency of oil-filter bypass events Thinner oil film in certain areas of rings Increased time at startup for the lubrication system to pressurize If the oil flow is too little, oil may not even reach certain areas Due to the reduced oil flow, slower refreshment rate of antiwear additives Due to the reduced oil flow, lifetime of contaminants before they get filtered out in the oil filter is longer VVT, VVL, and similar hydraulic valve systems may not work probably if the oil is too thick ... Just use the recommended viscosity and you will be fine. You can use slightly thinner or thicker if you like but there is usually no need for such things perhaps unless you have worn valve-stem oil seals and you need thicker oil to reduce oil metered through the valve guides. Or perhaps you want to tow or race uphill etc.

[removed] GM V8's were originaly spec'd for 5w-30, and we run 20w-50 and SAE 60 in them with no internal modifications aside from brass freeze plugs. How many of the issues you listed do we run into? None of them. I do know that if you run 5w-30 in them, that engine is going to have a much shorter life, particularly the big blocks.

 

[Gokhan]

Originally Posted By: DoubleWasp

Originally Posted By: Gokhan

Originally Posted By: DoubleWasp

You haven't posted the data to support that. There's only two cars posted up.

I posted 30 cars in the last list. I can't post the entire CR Web site for obvious copyright reasons and wouldn't have time to do so anyway. However, all Lexus and Toyota cars are top-rated in reliability. Other Japanese cars also rate very well. Worst-rated cars are European cars. Subscribe to CR ($20 a year) and look at them if you are interested.

Your list includes Japanese cars running 0w-20.

Four Subarus, two Volvos, one Chevy, and 23 German cars.

 

[PimTac]

Could we see some written evidence from a noted automotive journal, not a consumer fake news publication? CR has no real credibility. Another point: it could be said that these failures were caused by CAFE standards being pushed and rushed through. It doesn't escape my mind that many of these failures are happening while manufacturers are being pushed to produce more fuel efficient engines. The trend of lower displacement with turbocharging and direct injection may not blend well with grocery getters and other short trippers. The resulting carbon issues are the result. Blaming the oil is a diversion.

 

[DoubleWasp]

Originally Posted By: Gokhan

Four Subarus, two Volvos, one Chevy, and 23 German cars.

Defeating your claim of the infallibility of the Japanese/0w-20 combination.

 

[Gokhan]

Originally Posted By: DoubleWasp

GM V8's were originaly spec'd for 5w-30, and we run 20w-50 and SAE 60 in them with no internal modifications aside from brass freeze plugs. How many of the issues you listed do we run into? None of them. I do know that if you run 5w-30 in them, that engine is going to have a much shorter life, particularly the big blocks.

SAE 60 sounds great in a modern GM engine that recommends 5W-30. Where do you even find SAE 60 these days? It's not 1926 anymore.

 

[OVERKILL]

Originally Posted By: Gokhan

Originally Posted By: Shannow

Originally Posted By: Garak

Originally Posted By: Gokhan

Excessive oil pressure Reduced oil flow

How do we define "excessive" oil pressure? Where are we getting reduced flow?

And where in any engine does this impact lubrication...empirical evidence only, not motherhood statements about "obviously" and "feeling".

Some effects of increase in viscosity:

• Excessive heat generation resulting in oil oxidation, sludge and varnish build-up
• Gaseous cavitation due to inadequate oil flow to pumps and bearings
• Lubrication starvation due to inadequate oil flow
• Oil whip in journal bearings
• Excess energy consumption to overcome fluid friction
• Poor air detrainment or demulsibility
• Poor cold-start pumpability

Source: Viscosity: a lubricant's most important characteristic -- Parker Kittiwake

Let's compare the two viscosities being discussed in this thread rather than hyperbolic claims loosely based on some PDF that happens to support one's spurious posit. Mobil 1 15w-50 has the following viscosity characteristics: Viscosity @ 100ºC, cSt (ASTM D445) 18 Viscosity, @ 40ºC, cSt (ASTM D445) 125 Mobil 1 EP 0w-20 has the following viscosity characteristics: Viscosity @ 100ºC, cSt (ASTM D445) 8.6 Viscosity, @ 40ºC, cSt (ASTM D445) 44.9 Let's plug these puppies into a visc calc. Yes, we know the low temperature difference is going to be significant, but of course the thicker oil will, due to more viscous shear in the bearings, heat up quicker. At 115C, the 15w-50 is 13cSt, the same viscosity as the 0w-20 at ~81C. As the heavier oil gets hotter, it is going to get thinner, so even if there's a 10 degree variance (which I wouldn't describe as "significant" as per your earlier language and I would be surprised if it was even that big) then the variance between the two oils in viscosity is actually less than one would be led to believe. Let's say we DO have a 10C difference however. And let's say our operating oil temperature with our 0w-20 is 110C. That gives us 7.1cSt for the 0w-20, and if our 15w-50 increased oil temperature to 120C, then it would be 11.8cSt, or the same as the 0w-20 was at 85C, a far cry from "significant" and would be well within the temperature and subsequently viscosity variance experienced during seasonal use. Now, that's not to say that any of this would be of benefit to your average application, but it isn't going to spell disaster either. The reasoning that drove Ford to spec 5w-50 for their engine in track use applications that otherwise spec'd 5w-20 is the same reasoning that drives GM to recommend this 15w-50 for use in their vehicles used under similar operating conditions. That relatively small buffer of viscosity can be the difference between a bearing getting wiped or not, which depends on HTHS, a part of this we haven't discussed. 15w-50 may be less than ideal for a particular application that specs 0w-20. And it might be a bad idea if that application experiences -20C. However, under appropriate operating conditions, other than some minuscule gas mileage and power penalties, it isn't the fire and brimstone being peddled here to support one's personal vendetta.

 

[Garak]

Originally Posted By: Gokhan

Some effects of increase in viscosity:

Those apply when using a lubricant that's grossly unsuitable for the application. Show me where in the source that we're looking at jumping grades while still falling within suitable grades for ambient. You use an SAE 40 in -40 C here, you're going to get cavitation and then some. You won't have flow, at least for a while. You won't have cold-start pumpability. But, a 15w-XX is suitable down to around -20 C or so. Basically, we're talking about multigrades that are suitable for the ambient temperatures in question as per oil selection charts all over the world, contemporary and historical. I sure as heck don't have a lot of use for a 15w-XX as a year round fill, but I have very unpleasant winters. Take a look elsewhere in the document. He also lists, right beside the bullet points you indicated, effects of decrease in viscosity, none of which are any more pleasant, either, nor any more realistic when grabbed just for the sake of making a point, with no context. Also note that the author is taking great pains to discuss not simply viscosity choice, but changes in viscosity during service, and lists specific condemnation points, with Noria as his source, with a 10% viscosity reduction being critical, while not condemning viscosity increase until 20%.

 

[CT8]

Originally Posted By: Gokhan

Originally Posted By: igs

In other words, German engines suck.

I wouldn't use that word. They are fun to drive, as they are powerful. However, they have never reached the reliability level of Japanese engines.

We call it fine German engineering.

 

[Shannow]

Originally Posted By: Gokhan

Some effects of increase in viscosity:

• Excessive heat generation resulting in oil oxidation, sludge and varnish build-up
• Gaseous cavitation due to inadequate oil flow to pumps and bearings
• Lubrication starvation due to inadequate oil flow
• Oil whip in journal bearings
• Excess energy consumption to overcome fluid friction
• Poor air detrainment or demulsibility
• Poor cold-start pumpability

Source: Viscosity: a lubricant's most important characteristic -- Parker Kittiwake

It's an advertising blurb...for a company that sells viscometers. You really ARE clutching at anything (again), aren't you. (BTW, I think that I'm the only one on the board who has ever had to manage oil whip...I KNOW how that relates to this particular discussion, on this particular sub-board. To even introduce it into this discussion is inane)

 

[Shannow]

Originally Posted By: OVERKILL

Originally Posted By: Gokhan

Why would you elevate your oil temperature substantially by running three viscosity grades heavier? The worst thing that is happening on the seals, including valve-stem oil seals, is the oil temperature. Higher the temperature faster they will harden and fail.

Data please. How much hotter are we talking about here that justifies the use of the word "substantially" or is this just baseless posit?

https://bobistheoilguy.com/forums/ubbthreads.php/topics/3464122/Re:_Aviation's_Version_of_Mobi#Post3464122 Given the absence of facts to support his position, here's some facts that I'll share.

Originally Posted By: Shannow

I decided to test that this morning, on my Briggs Quantum mower. Have been using 5W20 synthetic through winter (grass hasn't died off at all this year it's been so mild). Mowed this morning, then left it sitting at the Governor for 10 mins or so. Temperature of the oil (thermocouple down dipstick hole) was 87C. Changed oil to 20W60...97C.

Bookends of 5W20 ILSAC oil (with MoDTC) in my air cooled mower on the governor versus 20W60... That was bulk oil temperature...with the valves exposed to combustion temperatures, I doubt that a 10C increase in bulk oil temperatures is going to be seen at the valve stem seals.

 

[TheKracken]

Originally Posted By: TheKracken

Originally Posted By: Shannow

Originally Posted By: TheKracken

I would argue that the flow argument put forth by the thin oil guys on this forum makes more sense.

They keep talking "flow", but then refuse to engage the part where the flow is dictated by the "positive displacement pump" that can only ever "flow" a certain number of millileters per engine RPM... Except at the limits of pumpability, and the "W" rating comes in....but that's an inconvenient truth Note, "flow" doesn't lubricate. And when the oil is within it's pumpable range (i.e. it's well above the limits of it's "W" rating), it fills the galleries, and gets to the remote ends at pretty well exactly the same time.

Looked up positive displacement pump and it is starting to make more sense (assuming most vehicles use this sort of pump?) How about the argument that a thinner oil will be closer to desired operational viscosity before a thicker oil will. It will at full operating temperature be thinner than the desired visc. but since the majority of wear is said to happen at start up and warm up this might mean that a thin oil will produce less wear than a thicker oil might. Then once you are at proper oil temp we have to see more about if a thin oil is enough to protect your engine within the designed operational temperature. Obviously exceeding this is going to thin out your oil and that safety margin will close pretty quickly.

Any thick oil guys have anything to say about my comment? I am neither in the thin or thick oil camp but have seen and felt benefits from converting the minivan to thin oil

 

[Shannow]

Originally Posted By: Shannow

That was bulk oil temperature...with the valves exposed to combustion temperatures, I doubt that a 10C increase in bulk oil temperatures is going to be seen at the valve stem seals.

FKM/viton...As, I believe are used in Toyota valve stem seals...

 

[Shannow]

Originally Posted By: TheKracken

Originally Posted By: TheKracken

How about the argument that a thinner oil will be closer to desired operational viscosity before a thicker oil will. It will at full operating temperature be thinner than the desired visc. but since the majority of wear is said to happen at start up and warm up this might mean that a thin oil will produce less wear than a thicker oil might. Then once you are at proper oil temp we have to see more about if a thin oil is enough to protect your engine within the designed operational temperature. Obviously exceeding this is going to thin out your oil and that safety margin will close pretty quickly.

Any thick oil guys have anything to say about my comment? I am neither in the thin or thick oil camp but have seen and felt benefits from converting the minivan to thin oil

First, I'm interested in what benefits that you've both observed and measured...can answer that later. Assuming that you checked BrocLumo's post which included corrosion and those effects that occur during warmup. Yes, that was one of the statements in oil 101 prior to it being revisited. The fact is that the first 20 minutes of wear is equivalent to the next number of hours of at temperature operation....it's not ALL at start-up as the smoke and mirrors thin oil pundits would have you believe. On start-up, there's already a layer of cold, and very thick oil in the bearing clearances, piston skirts and rings...if you've pulled apart an engine, there's no "dry" at that point. It will carry you satisfactorily through the next 10 seconds. In the first ten seconds from starting, the oil will get where it needs to be. If it's 0C, then anything from 0W20 to SAE30 will get to the remote ends at the same time. If your starting temperature is lower you NEED to start moving down the "W" grades to maintain this. The parts aren't at their operating temperature (therefore size and shape), so there's wear taking place there too.. As the engine warms up, as BrocLuno pointed out, there's condensation and corrosion taking place...irregardless of oil viscosity. There's a couple of pundits who claim that the "flow" of a thinner oil will carry away these products, and reduce wear...but carry them where exactly ? Then as the warm-up takes place, the viscosity thins, and parts come closertogether as hydrodynamic film thicknesses reduce...the temperatures at this point aren't sufficient to activate the additives, whoch shouldn't be a problem, as the tribofilm from the last number of runs is there...BUT, the sequence IVA wear test that all engine oils have to pass to get to approval demonstrates that this effect is significant. The engine is purposely held at around 65C, where the oil is thinning and the additives aren't functioning, on a new metal surface. As one of the oil forumators on the board stated, it's the "perfect storm" effect of diminished viscosity versus additive activation. He has operated at a lower temperature (more viscosity) and seen lower wear. Run the test at a higher temperature (more additive activation) and see less wear. So the effect is there. So IF you had an oil that was (to quote the old 101) 10cst at all temperature points, you would also need to engineer and include additives that were functional at every point in the operating range, they would need to be functional at 0C, (or -40C)...so no, I don't actually see a constant viscosity oil as an advantage...unless the additives are invented and included to match it.

 

[DoubleWasp]

Originally Posted By: Gokhan

SAE 60 sounds great in a modern GM engine that recommends 5W-30. Where do you even find SAE 60 these days? It's not 1926 anymore.

SAE 60 has its place. People ignorant enough to think of oil grades in terms of timeline would not know.

 

[TheKracken]

I am still reading more on your post and others in this thread as well as others. Trying to reach a conclusion on thin vs thick still. As for the benefits I have noticed...they are simply observations from my wife and I on our minivan. Seems to idle more smoothly, the throttle response in the lower end has been most noticeable. In the higher rpm range though power seems to be down. Also on the other end I put 5w30 in my honda insight hybrid specd for 0w20 and it seemed ever so slightly more slugish. None of this was any more than my butt dyno.

 

[PimTac]

It's good to see some factual information posted here that is explained well, versus so called speculation purported as facts and substantiated by questionable charts and reports. The clinking beer mug thing is a in your face insult that a kid would use. I'm not a thick or thin oil person. I believe in using what the manufacturers spec for their vehicles. But I do scratch my head when 0w-20 is specified for a TGDI engine like the Honda 1.5. Now, with the recent news that Ford is moving back to 5w-30 on their eco-boost engines, that is also telling me that the thinner oil were not enough to hold up in these TGDI engines. A Kia I am looking at with their 2.0 TGDI motor is going with 5w-30. Is the tide turning?

 

[Gokhan]

Originally Posted By: PimTac

The clinking beer mug thing is a in your face insult that a kid would use.

No, it's a commonly used smiley here that means "cheers."

 

[igs]

Originally Posted By: TheKracken

Any thick oil guys have anything to say about my comment? I am neither in the thin or thick oil camp but have seen and felt benefits from converting the minivan to thin oil

Here is the solution to all your problems.

 

[Gokhan]

My main criticism of "thick-oil people" is that they believe that there is really not an optimal viscosity for wear protection and the engine wear will uniformly decrease when you keep increasing the oil viscosity. They believe that even if you don't notice a difference, margin of protection against wear will always keep increasing with increasing viscosity. Any reasonable person knows that too much of a good thing is a bad thing and any engineer knows that there is an optimal range with minimums and maximums for almost any engineering design. In fact, there is actually a mass-reported case of thicker oil resulting in more bearing wear than thinner oil. It's the case of BMW M3 engine. Users reported severe bearing wear and bearing failures with the BMW-recommended Castrol 10W-60. The bearing wear was mostly gone when they used the much thinner Mobil 1 0W-40 instead. Oil starvation due to insufficient oil flow because of too small bearing clearances was possibly the reason, but it has never been resolved. Sure, it was a bad bearing design in this case and BMW issued technical bulletins about the bearings that came with too little clearances. Nevertheless, it shows that there is an optimal viscosity range for a given engine and thicker oil does not always result in less wear. Sometimes thicker oil is too thick and it could harm the engine. BMW M3 engine bearing failures: Castrol 10W-60 vs. Mobil 1 0W-40