I almost bought the Motorcraft diesel oil in auto zone jus now but I hesitated when I saw this



Right at the bottom it says do not use in gasoline engines with a catalyst. Doeso my 95 250 have a cat? My apologies for the stupid questions I just don't wanna mess up my motor.
Thanks

 

I use Shell Rotella diesel oil in my 92 F150 with a 5.0 and never had a problem. It keeps the engine real clean. I don't know how the oil could affect the cat.

 

I used Motorcraft 10W-30 in my '87 Bronco and got 295K miles on the original 302 before it spun a bearing.

 

I'm really having a hard time deciding because the guy I bought the truck from was using 15w40 so I jus want to keep it running with no issues

 

Then call them up and ask what brand. I know many folks are using the Shell Rotella because it contains zinc. Zinc is flat tappet cam friendly.

The PO may be using 15W40 to mask a low oil pressure issue.

 

A lot of people buy Rotella 15w40 in bulk and run it year round in everything, truck, car, tractor, lawnmower, etc. They don't want or need seven different oils laying around.

 

It's because the zinc and other ingredients are known to be hard on catalytic converters. I doubt using it will hurt anything, i run Rotella 15w40 in my 95 with a cat and have no issues. I think its posted for avoiding warranty complaints in the case of a failed "sniffer" test.

 

Yea the zinc/zddp content is hard on the cat, which is the reason for the warning. bit on the flip side, not having the zinc in the oil is hard on the cam.. Replacing the cat is cheaper than wiping the cam lobes off.

I'd keep using the diesel spec oil, personally, and I do. Much less worried about the cat than I am the cam.

edit: assuming you don't have the 5.8L engine with roller lifters already. If you have a roller engine then the zinc isn't needed..