For starters, I let the dealership change the oil in my 2 F-350's with V10's because my trucks do not fit well in the garage and outside at -40F is no fun.

My problem is with my Bobcat loader with a turbo-charged Kubota V2003 engine. I ran the stock oil in it until the first oil change at 75 hours (should have been 50 hrs, I thought 100, found out at 75). Changed to Mobile 1 5-30, probably shouldn't have switched to sythetic this early, but too late now. The engine has burned about half a quart (6 or 7 quart total capacity) before the second oil change. Changed oil at 250 hours (recommended interval) to Mobile 1 5-30 again. The oil is definately is black by the change interval, but does not look as if it is foaming.

I found this forum and have been reading about oils and looked at what I was using versus what the manual recommends. The manual requires a CD, CF4, or CG4 oil with the viscosity depending on the ambient temperature. The Mobile 1 does have a API CF rating and the Mobile website states that it is acceptable for diesels. I believe that it may not contain enough detergents and anti-foaming additives for diesel engines, so I am considering switching to Shell Rotella T synthetic 5-40 (API CI4, CH4, CG4, CF4, & CF rating).

Am I correct in assuming that I should not be using Mobile 1 in my diesel engine application? I now have about 275 hours on the machine, only 25 hours since the last change. If I change it out now to the Shell Rotella T synthetic, should I run it a short period of hours then change the oil and filter again to maintain a "pure" system (no residual Mobile 1)?

 

Can't get into most of your question, but I would definitely not continue to run a CF rated oil when it calls for CF-4. I don't think the CF is near as robust as the CF-4. Also, I don't see any problem with residual Mobil 1. The amount would be insignificant.

Do you have a beater car you can put the used Mobil 1 in? It probably is good for a couple thousand more miles, I would think.

 

I believe that you are correct on both counts.


I would not worry too much about residual Mobil1. I sure would not throw away perfectly good $5/qt. oil.

 

Try using Delvac -1, its a diesel full synthetic oil made by mobil.

 

I checked out the Delvac 1 on the Mobile website and it looks as if it meets all the specs I need. Now I will just have to check on prices. The Shell Rotella T is not too expensive if I by it by the 6 gallon case, $20.78/gallon or $5.20/quart.