Motor Oil Spec

[Drollins]

I searched here and couldn't find an answer. My truck did not have the operators manual for a diesel engine. What were Fords requirements for motor oil? I know that we all have our opinions about what is best and maybe there is not one correct answer but what did Ford say in 1991 was the correct viscosity and API rating for an IDI? Was single weight OK in certain temperature ranges etc? I have 10 gallons of Chevron 40w API CF that I don't know what to do with. If it is not OK to use in the summer months I guess I can mix it with diesel fuel and burn it. At least it would be worth $4 per gallon.

 

[Andertusa]

I don't know SPECIFICS about what Ford SPECIFICALLY called for, but GENERALLY, diesels run in the 15W-40 weight range.

 

[FordGuy100]

IDI's, unlike newer engines...aren't to picky about oil. Some may burn off faster than others (the old Rotella vs Delo), but really, with a 3K mile oil change, just about any diesel motor oil will work fine.

If your worried about specific weights of oil, just get yourself a oil pressure gauge, that way you can monitor what its like and adjust accordingly.

 

[Drollins]

I agree that IDI's are probably not too picky about lube oil. With such low HP to displacement and no emissions controls they really shouldn't care. But I was just curious about Fords recommendations. 20-30 years ago the use of single grade oil in diesels was the norm. Thanks for the replies.

 

[FarmerFrank]

I'd run straight 40 if I had it, but that's me.

 

[OLDBULL8]

Thirty forty years ago most all Diesels ran a 15w40 Vis oil. What you have is perfectly fine to run in the Summer months, as long as it's rated for Diesel use. A Diesel rated oil has additives to keep the Ash/Blowby in suspension, so that the engine doesn't get all sludged up. When you run out of the oil you have, you can then choose what you want to run.