Hi Craig,

The oil DOES care about the ambient temperature..... but only for starting.

I wonder what the highest Cx rating that any non synthetic 10W40 oil has. The highest ratings in the past have been in 15W40 oils but with the improved addatives, there may be much better 10W40 petro oils now than the best 15W40 oils of 20 years ago.

Personaly, I think if a modern engine needs an x50 oil, there is something wrong with it.

__________________
Ron Schroeder
'85 300 Turbo Diesel 2 tank WVO
'83 300 Turbo Diesel 2 tank WVO
Some former WVO vehicles since ~1980:
'83 Mercedes 240D
'80 Audi 4000D
'83 ISUZU Pup
'70 SAAB 99 with Kubota diesel
'76 Honda Civic with Kubota diesel
'86 Golf
Several diesel generators
All with 2 tank WVO conversion
LI NY