High or Low Viscosity.

[Pablo]

It really is disheartening to see all the sarcasm and negativity in some of these posts.

Well without hard proof we are stuck were we are always stuck. Thick vs thin.

I agree on a couple/three quick things.

"Excessive viscous" oil is not good in a application where this relatively high viscosity is not needed, leading to possibly more wear on start up in cold climates and flow problems, more wear in applications with tiny oil ports/passages and extremely small wear surface gaps

Ultra low viscosity is not better in a high load, high heat, heavy duty applications with large oil ports and large wear surface gaps

Of course there is sweet range, most cars it is a bit wider than shown in the OM. Hence people running 30 and 40 range oils in 20 recommended range engines probably does not cause harm.

 

[ZZman]

Well without hard proof we are stuck were we are always stuck. Thick vs thin.

I agree on a couple/three quick things.

"Excessive viscous" oil is not good in a application where this relatively high viscosity is not needed, leading to possibly more wear on start up in cold climates and flow problems, more wear in applications with tiny oil ports/passages and extremely small wear surface gaps

Ultra low viscosity is not better in a high load, high heat, heavy duty applications with large oil ports and large wear surface gaps

Of course there is sweet range, most cars it is a bit wider than shown in the OM. Hence people running 30 and 40 range oils in 20 recommended range engines probably does not cause harm.

That was much nicer and helpful....

 

[Al]

Well without hard proof we are stuck were we are always stuck. Thick vs thin.

I agree on a couple/three quick things.

"Excessive viscous" oil is not good in a application where this relatively high viscosity is not needed, leading to possibly more wear on start up in cold climates and flow problems, more wear in applications with tiny oil ports/passages and extremely small wear surface gaps

Ultra low viscosity is not better in a high load, high heat, heavy duty applications with large oil ports and large wear surface gaps

Of course there is sweet range, most cars it is a bit wider than shown in the OM. Hence people running 30 and 40 range oils in 20 recommended range engines probably does not cause harm.

I thank all even for your sarcastic comments, really. And yes after decades on BITOG. Again I do no longer have complete faith in Blackstone- I have said that. I do however know that high metals are an indication of tangible wear. I have talked to Mobile lubricating engineers back in the day when I worked for a living.

I don't think there is any difference in startup. At 30F. where viscosities are 15 to 20 times that of 210F. Grades at cold temp mean little.

 

[Sequoiasoon]

I have the M1 0W-40 in my Accord. First time using that. I didn't notice any difference in a very quick, less than 1 second starting clatter, I think I need to do the VTEC actuator spring. The TSB for cam chain tensioner was already done at dealer. That made it better than when I first heard it but still hear a slight noise.

What I do notice over the 0W-20 in Accord is that it takes longer into my trip before the VTEC activates. Once motor warmed up more it works fine, just longer into warm up time. Nothing else different that I can tell. I'll see again next change as it will probably get 5W-30 Euro L.

The EC30 and and 5W-20/30 mix in my sons Forte seem to make that a lot quieter on start up piston slap noise. Maybe just rings freeing up or other but son, wife and I all noticed it's quieter at startup through first couple minutes. once warmed it's the same and pretty quiet overall. It was getting 0W-20 prior as that was most of my stash then.

 

[ATex7239]

When you’re arguing on the internet for M1 5W40 in everything then realize you’re wrong but now you’re in too deep to stop….

 

[Scott S]

I can believe a 22 year BITOG veteran started such a thread!

View attachment 210754

If I did it, they would have blamed the meds from surgery... LMAO

 

[ltslimjim]

 

[skippermatt]

Thic

 

[yowps3]

Pro of thick oil - better wear protection, oil hold up better to heat, less effected by fuel dilation.

Pro of thin oil - improved cold start, slightly cooler oil temps and possibly enhanced fuel economy.

 

[Bryanccfshr]

I think it’s easier to say that there are Principles we have learned over the years. More highs is better, but how much do we really need?

There is something to be said for better engine responsiveness when it isn’t fully up to temperature.

As a thickly I am ok running 0w16 with whatever Toyota dealer puts in it until they stop in my Corolla cross hybrid. . Itrunes great and most times I can’t tell the IC engine kicked on.

Yet I run m1 0w40 in the 2018 Tacoma. It’s good oil and I just want something I feel confident for 10k miles. Doesn’t mean I won’t change.

I don’t think it matters for well designed engines. Those of us who have remained here long haul are self selective maintenance and reliability biased people. Yet there are a much higher percentage of drivers out there doing fine with whatever their quick lube shop does for the . Maybe something in the middle but we are also entertained by the science and development of principles, at least I am.

 

[camrydriver111]

A while back I would have staked my life on Higher viscosity was better. After looking at hundreds and hundreds of UOA's. I no longer feel that way. My 10K miles of 5W-40 Mobil 1 on my '22 Forester was certainly ho-hum. Going to 0W-20 Mobil 1. I expect it to do at least as well as the 5W-30 and 5W-40. I am changing today.

The exact same thing happened to me.

How many times have you switched sides on the thick vs. thin debate?

When I started out in motor oil I used to be a thin guy and thought thin would be the best for Canadian cold starts. Then I started researching euro spec oils and thought HTHS was the best measure of engine protection combined with an additive package capable of extended OCIs. More recently...

bobistheoilguy.com

 

[Triple_Se7en]

Yet I run m1 0w40 in the 2018 Tacoma. It’s good oil and I just want something I feel confident for 10k miles. Doesn’t mean I won’t change.

I'll ask the same - as I asked member Al early in this thread.
Just curious why you use a 10k oil for the max 10k. The Oil producer (Exxon-Mobil) was not confident enough to list 11 or 12k use on the front label of the 0w40 Euro jug.

 

[TomYoung]

2,342nd "thick vs. thin" thread with a double helping of "UOA proves one is better" fallacy.

But you forgot to add the noise factor. You would have had a trifecta then.

True, but maybe, just maybe, this is the thread that settles it definitively , once and for all.

 

[OilUzer]

A while back I would have staked my life on Higher viscosity was better. After looking at hundreds and hundreds of UOA's. I no longer feel that way. My 10K miles of 5W-40 Mobil 1 on my '22 Forester was certainly ho-hum. Going to 0W-20 Mobil 1. I expect it to do at least as well as the 5W-30 and 5W-40. I am changing today.

Baby steps!

Instead of 40 to 20, why not stop at 30?

And since you like M1 and very long OCIs, I would try M1 EP 5/10W-30.