Talk Some Sense into an Oil Thickie?

[Jimmy_Russells]

Huh?

lol. Yeah that is completely wrong.

I tend to agree with you Geo, what matters is oil temperature... Vehicles have a cooling system for a reason. It doesn't matter if it's 120° out if the oil temperatures are normal. Nobody ever seems to talk about this. If you are tracking the car and it never goes over like like 220° you are fine with the 20 grade. However if the oil goes to 270° you're going to be better off with probably a 40 grade. Nobody is reaching those temps on the street.

A few times a year I go on a six hour drive through the mountains, in a big loop. I go early in the morning and admittedly drive pretty spiritedly for hours on end. It wouldn't surprise me if the engine isn't below 3k for 90-120 minutes at a time with a lot of that in the 4-5.5k range. I just did it a couple weeks ago and oil temp never once went over 215°.

 

[TiGeo]

lol. Yeah that is completely wrong.

I tend to agree with you Geo, what matters is oil temperature... Vehicles have a cooling system for a reason. It doesn't matter if it's 120° out if the oil temperatures are normal. Nobody ever seems to talk about this. If you are tracking the car and it never goes over like like 220° you are fine with the 20 grade. However if the oil goes to 270° you're going to be better off with probably a 40 grade. Nobody is reaching those temps on the street.

A few times a year I go on a six hour drive through the mountains, in a big loop. I go early in the morning and admittedly drive pretty spiritedly for hours on end. It wouldn't surprise me if the engine isn't below 3k for 90-120 minutes at a time with a lot of that in the 4-5.5k range. I just did it a couple weeks ago and oil temp never once went over 215°.

The only way I can see my oil temps really get higher than normal on the street are high-RPM extended "full send" sessions on roads like Tail of The Dragon etc. and even then it's 240 max.

 

[FCD]

Brand new car? use the spec'd oil, when the warranty is out, then you maybe could look into experimenting.
But just as an example, Aston Martin specs 0W-20 for their Twin Turbo V12...

 

[CBlantasio]

My dad once told me they used 5w in Indy cars, something about it flowing better and dissipating heat better. I like the 0-30 idea, just say you use the thinner stuff.

Absolutely use the 0W-20 oil! Here's the way I look at it: One of the functions of engine oil is cooling. This is especially important in a turbocharged engine. The high exhaust temps a turbo is subjected to means it needs plenty of oil flowing through it to help dissipate the heat. You DO NOT want a thicker oil for this application. The higher the viscosity, the slower the oil will flow. Slower oil flow equals less cooling. Less cooling is bad for the turbo. A 20-weight oil provides more than adequate lubricity for the turbo and also cools it more efficiently. Use the 0W-20!

 

[kschachn]

Brand new car? use the spec'd oil, when the warranty is out, then you maybe could look into experimenting.
But just as an example, Aston Martin specs 0W-20 for their Twin Turbo V12...

What’s the HT/HS of the specified oil? Far more important than grade, I suspect it is similar to VW 508 00 approval.

 

[kschachn]

Absolutely use the 0W-20 oil! Here's the way I look at it: One of the functions of engine oil is cooling. This is especially important in a turbocharged engine. The high exhaust temps a turbo is subjected to means it needs plenty of oil flowing through it to help dissipate the heat. You DO NOT want a thicker oil for this application. The higher the viscosity, the slower the oil will flow. Slower oil flow equals less cooling. Less cooling is bad for the turbo. A 20-weight oil provides more than adequate lubricity for the turbo and also cools it more efficiently. Use the 0W-20!

More important is film thickness and oxidation resistance. The difference in “flow” is negligible especially at operating temperature.

 

[mahanddeem]

I would run 5w30 or even a thin 0w40 and never think twice. Especially if you don't see harsh (0F or less) winters.

 

[DirectRejection]

Sequence IIIH.
Sequence IVB.
Sequence VH.
Revised.
For enhanced performance.
While at the same time,
improving fuel economy.
Backward compatible.
ILSAC has spoken.

 

[MRC01]

As I clearly stated in my original post above, it's more than likely that the OP isn't driving the car hard. How many people really "send it" in their daily cars that would require you to run a thicker oil? I'll say nearly 0%. Just b/c you have a quick little car like the Integra doesn't mean on your daily commute and accelerating hard to get on the highway you need special oil beyond what the OE says to use.

I mostly agree with that. One test is whether you're driving it hard enough to heat soak the engine. Like SCCA track events or continuous full throttle 2nd gear through curvy roads for 15+ minutes or however long it takes to overwhelm the cooling system and have the computer pull boost & timing, noticeably losing power.
If you are doing that, then the thicker oil makes sense. But most people aren't doing that.

 

[FCD]

What’s the HT/HS of the specified oil? Far more important than grade, I suspect it is similar to VW 508 00 approval.

Actually it's ILSAC GF-5, so not thick at all.
The thing is, engines can be designed to work just fine with low viscosity oils, even performance engines, i suspect those engines probably have nice thick wide bearings and journals, this means the load is more spread out and doesn't need as thick of an oil to prevent damage.

 

[FCD]

And i'm a "thickie" , i only use A3/B4 oils myself, i don't even consider using any of those thin low hths low saps stuff in my cars, but my cars are 34 and 47 years old...

 

[Silver]

No, We all want to think we are smarter than every engineer at Honda.

I get your point and it is valid, but on the other hand automotive engineers aren't exactly ... well, they are far, far from the authority on good design. Actually, I think a lot of them work from a cubicle in Pakistan now judging from some the things I'm seeing.

 

[Samurai1225]

I've been laying in the weeds with great interest on this post because this very question has crossed my mind many times. I drive an Accord with the 2.0 turbo DI engine spec'ed for 0w-20 . I think I am more confused after having read the replies. I run 5000 mile OCI 0w-20 and I am out of factory warranty period.

The bottom line for me is could I reasonably expect that my engine, with everything else being equal, last appreciably longer were I to run xx-30 or xx-40 weight oil?

 

[TiGeo]

I mostly agree with that. One test is whether you're driving it hard enough to heat soak the engine. Like SCCA track events or continuous full throttle 2nd gear through curvy roads for 15+ minutes or however long it takes to overwhelm the cooling system and have the computer pull boost & timing, noticeably losing power.
If you are doing that, then the thicker oil makes sense. But most people aren't doing that.

Correct.

 

[TiGeo]

I've been laying in the weeds with great interest on this post because this very question has crossed my mind many times. I drive an Accord with the 2.0 turbo DI engine spec'ed for 0w-20 . I think I am more confused after having read the replies. I run 5000 mile OCI 0w-20 and I am out of factory warranty period.

The bottom line for me is could I reasonably expect that my engine, with everything else being equal, last appreciably longer were I to run xx-30 or xx-40 weight oil?

As much as people here will speculate nobody knows this answer.

 

[Odd_Ball]

My dad once told me they used 5w in Indy cars, something about it flowing better and dissipating heat better. I like the 0-30 idea, just say you use the thinner stuff.

I don't believe that is true. I believe that low viscosity oils are used in race engines that are highly constrained in their displacement, air induction, fuel capacity, etc. so that they can eek out that last 1% of horsepower which can be the difference between 1st and 2nd or 3rd place in cars that are all very close in terms of performance. Since the engine will be rebuilt after each race, with respect to longevity they only care about making it to the finish line.

 

[ZeeOSix]

As of right now I'm planning to find a fully synthetic SP rated 0W-30, with the highest HTHS and lowest NOACK numbers I can find. Am I crazy?

No, you're not crazy ... more like someone who doesn't want to be on the edge of MOFT all the time. I'd do the same thing because I like headroom.

 

[ZeeOSix]

Read the manual like a lawyer and probably it doesn't really say you can't use a step up in viscosity. I also like to look what they recommend in other countries for the same motor. Usually it a step up in viscosity or show a temperature range for other grades.

I've never seen any owner's manual specifically say that if the "recommended" oil viscosity is not used that the factory warranty will be void.

 

[ZeeOSix]

Yep, and a lot of manuals say to run a thicker viscosity under high speed and/or severe conditions.

All the Toyota ownwer's manuals have a statement pertaining to that. Even the ones that call out to use only 0W-16.

 

[ZeeOSix]

I just looked at my 2021 Silverado's owners manual:

Use SAE 0W-20 viscosity grade engine oil for the 5.3L and 6.2L V8 engines.

Caution
Failure to use the recommended engine oil or equivalent can result in engine damage not covered by the vehicle warranty.

That's a pretty nebulous statement that could mean all kinds of things, like using an oil that doesn't meet the API/ILSAC spec, like some weird oil brand bought at the dollar store. And the words "can result in engine damage" are key. The oil would have to be proven that it caused the damage. Running a much thinner oil than what the OM recommends could actually do that, but no engine is going to be damaged if going up one grade above the recommended grade.