which 5w-30?

[kschachn]

Look at HTHS of a 5w30 vs a 0w30 from the same brand and why 0w oils lost BMW LL01/LL04 spec. They're not as robust.

That’s not the reason here. Look up the approval HT/HS requirements for this brand and you’ll see your statement isn’t correct.

That’s why approvals are so important. That’s what dictates the HT/HS and it’s not a different requirement for a different winter rating.

 

[svenson]

It helps to remember that grade is a recommendation not a spec. Engines are designed to tolerate a minimum HT/HS without excessive wear, an oil with a higher one is acceptable and often desirable.

we are talking about a minimum hths that engines tolerate. but how high hths can tolerate? always within approvals or more?
example..mine is from 3.5 hths ,0-30 to 4.0 hths a 5-40 redline e.x
can i go higher out of the approvals? can the engine tolerate higher hths? i know i wont do it,i know it has disadvantages, more drug,more fuel consumption etc. but can the engine tolerate a so higher? just wondered

 

[kschachn]

we are talking about a minimum hths that engines tolerate. but how high hths can tolerate? always within approvals or more?
example..mine is from 3.5 hths ,0-30 to 4.0 hths a 5-40 redline e.x
can i go higher out of the approvals? can the engine tolerate higher hths? i know i wont do it,i know it has disadvantages, more drug,more fuel consumption etc. but can the engine tolerate a so higher? just wondered

Is there an upper limit for any SAE grade? There are 70-grade oils used in Australia and there aren't warnings on the labels that the high HT/HS could damage some engines.

As long as the winter rating is appropriate for the starting temperatures, how would any grade damage the engine?

 

[svenson]

Is there an upper limit for any SAE grade? There are 70-grade oils used in Australia and there aren't warnings on the labels that the high HT/HS could damage some engines.

As long as the winter rating is appropriate for the starting temperatures, how would any grade damage the engine?

there arent any warnings but there arent any suggestions either.so if i have a 40 grade limit from bmw ,i can still use a 70 grade? what hths is that? 6-7? just curious

 

[edyvw]

Look at HTHS of a 5w30 vs a 0w30 from the same brand and why 0w oils lost BMW LL01/LL04 spec. They're not as robust.

What?

 

[kschachn]

there arent any warnings but there arent any suggestions either.so if i have a 40 grade limit from bmw ,i can still use a 70 grade? what hths is that? 6-7? just curious

This is where a bit of physics understanding helps, and how oil films work in an engine.

 

[scrllock]

This sounds like the old BMW forum rumor, that rod bearings were failing because the S65 came with 10w60 which was "too thick" for the clearances.