Hi all,

Thanks for the responses to my coolant problems post. Now I have another question.

I have read in my 940's owners manual that it should take engine oil with a classification of API SG/CD. When at the auto stores I see various oils with markings such as SJ, SF etc. Can anyone tell me what this classification means? Do I have to use this and only this classification? Can I use a synthetic with a different classification?

Thanks for any replies.

Roll on
Brad
91 940GL

These are American Petroleum Institute performance grades of oil. The higher the letter, the better the oil: the current standard is SJ, which is better than SH. See the API website for more details about what these mean.

You should have four concerns: API grade (all the oil sold by now should be SJ, with some older stocks of SH still being used up); viscosity (10-30 recommended, 5-30 in winter); the brand of oil (there are differences: Quaker State is reviled); and whether you use dino oil, a synthetic or a synthetic blend. For your car, a good blend would be fine: Mobil makes a fine product. Or synthetic: Mobil 1 is inexpensive and widely available; Amsoil better but a little more expensive.

to wit...they don't have to meet the volatility spec common to euro apps.
I was under the impression that no dino oil could meet the NOACK euro volatility spec and they were essentially all synthetic. My point was to avoid using SH spec oils until the volatility issue settles down, especially since his car was spec'd for SG (although I know the higher specs are supposed to be backward compatible...).

Not that it makes a difference to me...I only run amsoil in my cars anyway.

SH or higher synthetics are fine (although I personally avoid Castrol Syntec after reading some tests on Syntec's failure on the NOACK volatility test...).

Right.