Engine issues caused by thin oils?

[Astro14]

Your cars are not a great example since they are mainly European, and older. Mine is only five years old and also recommends C3 30 grade. Collectively the Germans at least didn't start recommending 20 grade oil until about four or five years ago, whether the engine was turbocharged or not. Of course the use case for those cars is a lot different over there than here as well.

I have a lot of experience with rebuilt turbochargers. My place of employment does at least a couple a week. Bearing failure is very rare, they almost always fail because of conditions external to the turbo.

Even if bearing temperature is 150°, or more, it clearly does not pose any problem long term to the life of the turbocharger. I know the viscosity is acceptable because I trust the engineering and I have seen it myself for well over a decade. There is also constant flow of fresh, 90-100° oil. Oil is only actually in the turbocharger for a few seconds, how much can it actually heat up?

End of the day most of the people here are concerned about their wife's daily driver or something, they aren't pulling 10k lbs through the Rockies, when this type of thing may actually matter.

Well, I would suggest that they actually are a great example of engine and turbocharger longevity. I credit both the oil cooler and oil specification on them for that longevity.

But, to your point, they do have different oil specifications than cars, even German and Swedish cars, built in the past couple of years.

Interesting that you car, as recently as five years ago, specified a -30 viscosity.

As far as the Rockies part, well, I used to drive a turbocharged car in the Rockies all the time. Still do. The one back then was turbocharged, as is the one now. I do push it. The boost is awesome, and at altitude, the car does really well compared with other NA cars on the road.

 

[Soft Cars]

As soon as oil gets down to 0W-00, these thick/thin threads will be over.

 

[Astro14]

As soon as oil gets down to 0W-00, these thick/thin threads will be over.

Don’t worry…I will have hoarded enough by then to avoid running the Packard on that stuff…

 

[Jimmy_Russells]

Well, I would suggest that they actually are a great example of engine and turbocharger longevity. I credit both the oil cooler and oil specification on them for that longevity.

I don't disagree with that. I just also feel that overkill isn't necessarily better. If modern oil, turbo, engine technology can reduce fuel consumption and emissions with very little or no penalty to reliability and longevity, I'm all for it. I know that may be contrarian to many here.

To be honest I thought you would respond that we don't have long enough timeline on 20 grades and turbocharging, at least not nearly as long as 30 and 40 grades. That is changing though, even my co-worker's 3.0 Duramax Sierra specs 0w20 Dexos D.

 

[Shel_B]

Even if bearing temperature is 150°, or more, it clearly does not pose any problem long term to the life of the turbocharger. I know the viscosity is acceptable because I trust the engineering and I have seen it myself for well over a decade. There is also constant flow of fresh, 90-100° oil. Oil is only actually in the turbocharger for a few seconds, how much can it actually heat up?

I'm unsure of the intent of your question, but it's a good question nevertheless.

I'd imagine that the film of oil running through the bearings of a turbo would be quite thin, perhaps similar to the clearances on various piston bearings such as wrist and pin bearings and crankshaft bearings. I'm just guessing. So, if there's such a thin film of oil, which is already hot, how much time would that oil need to reach a critical temperature and condition, one that would contribute to accelerated wear in the turbo and shorten its life?

 

[Jimmy_Russells]

I'm unsure of the intent of your question, but it's a good question nevertheless.

I'd imagine that the film of oil running through the bearings of a turbo would be quite thin, perhaps similar to the clearances on various piston bearings such as wrist and pin bearings and crankshaft bearings. I'm just guessing. So, if there's such a thin film of oil, which is already hot, how much time would that oil need to reach a critical temperature and condition, one that would contribute to accelerated wear in the turbo and shorten its life?

A bearing in a turbo is exactly the same as one in a rod or main journal (other than a ball bearing turbo obviously). Clearly the turbocharger operates in hotter conditions than a crankshaft, but how much of that heat is transferred into the actual oil temp, I don't think it's that much. The oil simply flows through it too quickly.

 

[sk_pete]

The HTHS of 20 grade oil at 100°C is over 4.5

but not all engine parts have same temperature

 

[shDK]

Don't think the 0-16 and 0-8 oils have been in use long enough to see engine problems. Anybody seen a Toyota with well over 100k using 0-16 oils? Why do they still go with 20 wt oil in their V6's?

Actually. corolla sw, prius and RAV4 hybrids running 0w-16 oils are used a lot here as taxis. And 300.000 km is pretty normal.

 

[vavavroom]

Oil viscosity is the number 1 cause of anxiety disorders.

 

[twX]

The thin versus thick debate used to be between 20 weight and 30 weight oils. The reason there was no answer to that debate was that 20 weight oils still had the HTHS = 2.6 when new, which provided adequate protection on the HTHS wear graph with HTHS = 2.6 being the minimum for adequate protection.

But 16 weight or 8 weight are different oils entirely (breaking the HTHS wear graph's 2.6 minimum for adequate wear protection), and it's an unknown how an engine using 16 weight or 8 weight oil will hold up after 200k or 300k miles.

but not all engine parts have same temperature

Those HTHS vs wear charts were produced by testing engines with oil sump temperatures of 130 to 150 degrees C. Those tests already take into account the fact that there will be some additional temperature rise in the bearings, piston area, etc. So, the minimum high-shear viscosity of oil in the sump that provides adequate protection is 2.6 cP, but the minimum viscosity of oil in the hotter parts of the engine would be significantly lower. For example, assuming a temperature rise of around 30 C in the piston area, the oil in that part of the engine would have been only around 1.8 cP, and yet it still provided adequate engine protection in these studies.

 

[bigjl]

Hi all.

All over the internet, partly also on this forum. People are having a hard time accepting thiner and thinner oil. I have read a lot of arguments for and against thin oils.

But..are there actually any cases where engines have reliability problems. Where it is proven it is because of thin oils. Let's say 0w-16. And I mean where it can be proven that the manufacturer actually spec too thin oils.

Have a nice day.
kindly
Søren

VAG specify 0w20 508/509 on lots of their newer cars in the UK.

They are pretty strict when it comes to what top up oil you can use.

Only 1/2 litre of 5w30 meeting 504 for example in a 2020 Q2

 

[vavavroom]

The anxiety caused by oil viscosity can further lead to more serious disorders.

Paranoid personality disorder: They spec the wrong oil so my engine will wear out soon. And the treehuggers are in on it, too.
Schizophrenia: My engine rattles with thin oil but I can't tolerate the startup wear from thick oil.
Impostor Syndrome: I put Wolfshead in Red Line bottles to fool others
Obsessive-compulsive disorder: I compare oil viscosity specs of very similar products for hours every day and I have to call the Mobil tech department later to confirm my findings.
Dependent personality disorder: I realize my inability to choose the perfect oil and feel worthless. I'm looking for help on an oil forum.

You guys are lucky I'm not a Freudian.

 

[bigjl]

Don't think the 0-16 and 0-8 oils have been in use long enough to see engine problems. Anybody seen a Toyota with well over 100k using 0-16 oils? Why do they still go with 20 wt oil in their V6's?

Maybe because the V6 is an old design and was never intended to use such a thin oil?

But the newer engines, and hybrids, were likely designed to run the thinner oils from the start

Two previous cars I have owned that specced 0w20 or 5w20 were also specced for thicker oils, the exception being the 2020 Q2 which is 0w20 apart from allowing a 1/2 litre tip up of a thicker oil if you can’t find 0w20, which you will struggle to find outside the VAG dealer network or without ordering it.

The other two were a 2014 Kia Picanto 1.0 City and my 2020 BMW 745Le PHEV

In both cases the dealers use one of the 5w30 options, not the 0w20 or 5w20

I did put 5w20 in the Picanto to see what difference it made, it seemed a little noisier to me, it might have been a little bit more responsive when revving but that was likely wishful thinking.

I don’t think I will do the same on the BMW, I think my interim change will be 5w40 LL04 of some kind

 

[kschachn]

The anxiety caused by oil viscosity can further lead to more serious disorders.

Paranoid personality disorder: They spec the wrong oil so my engine will wear out soon. And the treehuggers are in on it, too.
Schizophrenia: My engine rattles with thin oil but I can't tolerate the startup wear from thick oil.
Impostor Syndrome: I put Wolfshead in Red Line bottles to fool others
Obsessive-compulsive disorder: I compare oil viscosity specs of very similar products for hours every day and I have to call the Mobil tech department later to confirm my findings.
Dependent personality disorder: I realize my inability to choose the perfect oil and feel worthless. I'm looking for help on an oil forum.

You guys are lucky I'm not a Freudian.

Unfortunately this is pretty much where thick vs. thin threads end up. A void of actual technical discussion (apart from political considerations) leads you here.

 

[wemay]

 

[Astro14]

OK. Looks like the serious discussion has ended. Lock time.

Suggested BITOG rule: one thick v. thin thread open at a time.

Just because they always end up off the rails.

Don’t worry, I’m certain someone will start another thread in a day or two.