Do you really need any thicker than 0W-20?

[Gokhan]

I did it. I ran PYB dino 5W-20 for 5k miles and then Toyota synthetic (by ExxonMobil) 0W-20 for 5k miles. The car was driven hard, full-throttle in California/Nevdad desert heat, and had a lot of short trips. Results? The engine runs smoother every day and smoother than ever in recent years. There is hardly any oil consumption. Wear metals are very low.

UOA Toyota (TGMO) 0W-20 SN, 5,306 M, 85 Corolla 4A-LC

Does anyone think that using thicker oil would improve this UOA? There is this myth about thinner oil being only suitable for newer engine designs but I don't seem to have any problems running 0W-20 in a 28-year-old engine.

The warm-up benefits of ultra-high-viscosity-index oils like Toyota 0W-20 are huge, as you don't have to worry about poor lubrication efficiency because of viscosity being too high during warm-up.

Is there really a gas-engine automotive application that really requires thick oil? Diesels, which generate a lot of abrasive soot particles, are a different story of course.

 

[d00df00d]

As far as I know, thick oil is mainly for:

1. Loose piston rings
2. Huge oil temps

 

[nitehawk55]

You're gonna stir things up with this question

..... but my feeling is no for the most part unless severe service in very hot climate or if the engine is starting to show a lot of oil use due to wear causing oil shear or low oil pressure(a thicker oil may or may not help), otherwise 0W20 is fine

 

[sciphi]

Turbos and direct injection. A small engine running a turbo can see in excess of 250*F oil temperatures in normal driving. Depending on how hot it gets, a manufacturer that wants a 30 weight at temperatures above 100*C (212*F) that the hot viscosity is measured at just might specify a 5w-40 or a very high viscosity 5w-30.

Direct injection likewise can thin out a oil with fuel quite rapidly. A high-VI 5w-30 might be just the ticket in that case, also.

Considering the number of turbocharged, direct-injected engines on the market today, 30 and 40 weight oils are here to stay.

 

[mongo161]

I run a 1997 Toyota 4 Runner, SRV and Mobil 1 still ONLY reccomends 10w-30 for use in the V6.

Now I'm running a blend of 4 quarts of M1, EP, 5w-20 and 2 quarts of M1 15w-50 and my engine runs fine. I've ran this oil since last September with almost 7K on the oil with no oil added as make up oil. The engine ran really smooth all winter long.

Strange, Toyota had back spec'd my 4Runner for 5w-20 but the M1 folks said ONLY run 10w-30.....but I also run blended mixes and 5w-30. I really wonder which group is right????

Toyota or M1???

 

[MinamiKotaro]

My Ion is spec'd for 5-30, I'm running 5-40 "Euro" at the moment. I think I'll try 5-20 or 0-20 next.

Why? Just for the [censored] of it.

 

[Barkleymut]

Because you can run anything in that Ecotec....

 

[RiceCake]

Anything with a limpwristed oil pump is also likely a contender for a thicker oil being necessary to maintain pressure.

 

[CATERHAM]

The answer to your question is obviously not.
So when Honda comes out with their 0W-16 later this year are you going to try it?

 

[Shannow]

I think that 20s have most bases covered.

 

[aquariuscsm]

20 wts are probably perfect for a 4-banger. Anything thicker would probably slow them down. A muscle car engine would probably destroy itself on a 20 wt.

 

[Trav]

Of course there is a need for oil with higher viscosity.
If the bearing clearances are larger like in many high HP or worn engines or the surface area of those bearings is too small you will wipe a bearing.
The oil pump type and pressure also plays a large roll in the equation.

From a technical standpoint the crankshaft must be either forged or hardened and be stiff enough to eliminate flex.
The more main bearings the better, thats the reason some 4 bangers with 5 mains are able to get away with running it without a forged crank.
The low clearance bearings would be quickly wiped out with a crank that flexed.
This alone knocks a lot of engines out from running light viscosity oil.

Anyone that says a low viscosity oil can be run in any engine is just running off at the mouth.
Knowing how the engine is constructed will determine if its a candidate for low viscosity oil not the amount of VI.

 

[CMMeadAM]

Originally Posted By: Shannow
I think that 20s have most bases covered.

Quite obviously, the range shown for Toyota 0W20 is more than a little ABSURD !

 

[Gokhan]

Originally Posted By: CATERHAM
The answer to your question is obviously not.
So when Honda comes out with their 0W-16 later this year are you going to try it?

Well, there is obviously a limit to how low you can go without starting to wear your engine too much.

I like Toyota 0W-20 SN (by ExxonMobil) because even though it's 0W-20, it's not much thinner than a 5W-30 when hot, especially a sheared 5W-30. On top of that, you have the ultra-high viscosity index, which makes it relatively thin before it reaches the normal operating temperature.

So, I would pass on the 0W-16 GF-6B if it came at this moment. In fact, API is so afraid that 0W-16 could damage older engines so that they are now creating two separate categories -- GF-6A and GF-6B -- and the GF-6B will not be backward compatible with any pre-2016ish car. This doesn't mean that it can damage your engine, but it will be so much thinner than anything we have right now that we don't know without seeing it in the field.

 

[Gokhan]

Originally Posted By: CMMeadAM
Originally Posted By: Shannow
I think that 20s have most bases covered.

Quite obviously, the range shown for Toyota 0W20 is more than a little ABSURD !

Yes, whoever made this chart, it makes no sense at all. You can use Toyota 0W-20 in any application requiring 5W-20 at all temperatures, with even better results. It might not beat the NOACK volatility of a few fully synthetic 5W-20s but that would be its only caveat.

 

[Zaedock]

The chart makes perfect sense.

 

[FoxS]

Originally Posted By: d00df00d
As far as I know, thick oil is mainly for:

1. Loose piston rings
2. Huge oil temps


3. Aussies

 

[FoxS]

Originally Posted By: Shannow
I think that 20s have most bases covered.

Fixed it for ya.

 

[Capa]

Originally Posted By: FoxS
Originally Posted By: d00df00d
As far as I know, thick oil is mainly for:

1. Loose piston rings
2. Huge oil temps


3. Aussies


Lol. Truth.

 

[CATERHAM]

Originally Posted By: Gokhan

I like Toyota 0W-20 SN (by ExxonMobil) because even though it's 0W-20, it's not much thinner than a 5W-30 when hot, especially a sheared 5W-30.

Don't be mislead by the relatively high KV100 viscosity which is largely a result of it's high VII content. It's still a 2.6cP oil and does have a much lower hot operational viscosity than a typical 165-170 VI 3.0-3.1cP HTHSV 5W-30.