I recently bought a 1998 '34 and noticed that on the oil cap it says " D10 W 30" but the manual says "SAE 30 HD (CD) or 10 W 40; which is it? I can't seem to find a 10 W 30 that is for diesel.
Solitude
If you use the engine in cold weather, using the multi-weight will make starting a bit easier.
Otherwise, 30 is preferable.
The key is to use oil intended for diesels, not gas engines.
Joel
Marine stores usually don't carry it.
Just go to an automotive store, like Kragen's, Pep Boys, Napa, etc.
You can also use synthetic oil. Many advantages, although a bit more expensive.
Stu
I have switched to Mobil 1. The engine starts easier and uses less. The additional cost is minimal. I change oil once per year. $8 or $15 doesn't make much difference.
Jim Kane
I use Texaco Ursa 10W30, which is made for diesel engines. I special order it by the case from Texaco products sellers. Doesn't cost any more. Interestingly, dealers, including the local commercial fishing gear supplier, usually stock Ursa 15W40. I won't use that up here in New England.
Mike Roy
Cat's Paw
1373 MkII