Protect for statup or extreme use?

[spot]

Often said that most engine wear occurs at startup. How about for an engine that operates a well above 230F in extreme heat. Say like an air cooled engine. A 0, or 5W - xy might protect against startup wear, but wouldn't a straight weight dino make the engine ultimately last longer? A moment of startup vs hours of extreme conditions. Air temp at start up is 70F, and 90 to 100 or above while being driven.

 

[Steve S]

It is a subject a little more complicated than you put it . Start up wear ??? Exactly what are you referring to? Using a straight 30 in below freezing startup temps? Or the higher wear that occurs untill the engine reaches operating temps to which nothing can be done about? Extreme high temps . Some syn oils are better . You can use with great success a straight 30 or 40 with startup temps at 70*f.

 

[HTSS_TR]

Every oil is too thick until it reach temperature of 150-160F or higher. But multi-grade is much thinner then straight grade at all temps below 212F, at that temperature they are about the same thickness. Most wear occurs before oil temp reach operating.

 

[FL_Rob]

For something air cooled with a pressurized oil system ,a strong multi-vis (15w40/50)is fine but just a splash lubed, I'd go straight 30 or 40.

 

[RISUPERCREWMAN]

Try some Mobil-1 V twin 20W-50 for Harley Davidson's! They operate at like 260 degrees +!

 

[Steve S]

Originally Posted By: HTSS_TR
Every oil is too thick until it reach temperature of 150-160F or higher. But multi-grade is much thinner then straight grade at all temps below 212F, at that temperature they are about the same thickness. Most wear occurs before oil temp reach operating.
The wear is not from the oil and to guess it is so is flat wrong.

 

[jorton]

Is it a passenger car? If so, the manufacturer probably recommends the grade that gives the best fuel economy.

If not, the manufacturer probably recommends the grade that protects best.

(Is it a passenger car?)