If 0w-20 in the winter why not 5w30 in the summer

[Shannow]

The majority of the heat that engine oil has to shift is that due to friction within the oil and moving parts, so it's unlkikely that a thicker oil can run cooler.

The majority of that heat has to be radiated out of the sump, using the temperature differetial that exists between the sump and the atmosphere. In order to MOVE more heat, it needs a greater deltaT

 

[Garak]

Originally Posted By: kschachn
You and the "hand to manifold" test guy should get together. You aren't him, are you?

They can all come here for a visit. With the G37, 10w-30, 5w-30, 5w-40, -35 C, +35 C, after 15 minutes of driving, you won't be getting grabby anywhere under the hood.

 

[T-Stick]

Originally Posted By: Shannow
The majority of the heat that engine oil has to shift is that due to friction within the oil and moving parts, so it's unlkikely that a thicker oil can run cooler.

The majority of that heat has to be radiated out of the sump, using the temperature differetial that exists between the sump and the atmosphere. In order to MOVE more heat, it needs a greater deltaT


Correct -- oil does dissipate heat thru the sump and outside temps make a difference. Again many manuals for trucks still specify a heavier oil for towing and/or in hotter temps. This is part of the basic engineering spec.

While 0w20 may perform well in most temps it certainly does not offer the same level of protection as an equally formulated 5w30 in hot temps. 0w20 offers advantages in cold temps because a lot of wear can occur over time with cold starts.

My point is that 0w20 probably offers the optimum protection in cold temps and 5w30 offers the optimum protection in hot temps. You could run either all year round for "satisfactory" results, but the thread was more focused on "optimum" results.

 

[dblshock]

I run 75-80mph at least 28hrs. a month, year round here... that's difficult on a xW-20..rings and cam assembly wear.

 

[dblshock]

...the chains just beat the snot from a 20 then throw on your cold weather fuel dilution and we got a mess, you have to go 30 or 40 to stay in spec.

 

[Garak]

Originally Posted By: T-Stick
My point is that 0w20 probably offers the optimum protection in cold temps and 5w30 offers the optimum protection in hot temps. You could run either all year round for "satisfactory" results, but the thread was more focused on "optimum" results.

Extending that logic, how about a 0w-30? After all, there are ILSAC, A3/B4, and HDEO variants available, so one can really take one's pick.

 

[igs]

10W30 offers more protection than 5W30 in hot temps.

 

[kschachn]

Originally Posted By: igs
10W30 offers more protection than 5W30 in hot temps.

A high HTHS 0W-30 is better than either one.

 

[SilverFusion2010]

I like my M1 HM 10w-30 with HTHS of 3.5

 

[T-Stick]

I would agree that a 10w30 or 0w30 would be good in a summer application also. I was just picking the most common option for a lighter 30 weight oil.