Oil Spec for m51a1 Multi-Fuel Engine???

[rickdavis81]

Just received my filter kit for my multi fuel from BigMikes. What oil do you guys suggest? Looks like it's straight 30wt. Seems like my other diesels always seemed to prefer one kind or another. Also just regular green antifreeze?

 

[BKubu]

15W40 oil. The brand is up to you. I buy whatever good name brand is on sale, but, all things being equal, I like Rotella. I have used Valvoline, Delvac, Rotella, and others. Regarding antifreeze, make sure it is rated for a diesel...cavitation (little bubbles forming to erode the metal) is always a concern.

 

[juanprado]

If this is the older M939 old school NHC250, I run plain green. When these engines first came out in the M809 and civilian world, plain green was the only option. Much debate on another thread about the newer stuff in the NHC250 but I believe the military in the m939 used regular A/F. The 8.3L and fmtv/lmtv, I would say to use the newer formula "diesel" approved a/f according to manufacture.

YMMV

 

[rickdavis81]

It's an m51a1 multi fuel. Guess I didn't realize there is diesel rated a/f

 

[juanprado]

I am not familiar with the multi fuel but since it is even older still, I would say green again because of age.

 

[WillWagner]

The multi is a dry liner engine, SCA's kinda don't matter for the cavitation issue, but a low silicate antifreeze is good so you don't wipe out wp seals.