Howdy,

I am new to the site. Three weeks ago I bought a 94 3/4 ton 4wd cummins automatic it has 147000 miles on it. The truck it great it runs really well I couldn't be happier, but I checked the oil yesterday after 800 and it had burned a little over a gallon of oil. It is not leaking on the ground anywhere so where is it going? Could the valves be the problem. I am pretty worried about this and I have no idea what to do. This is my first diesel, so any help would be appreciated.

Thanks,

John West
979-575-3306

 

Welcome to this site. Sorry to hear about your problem. Some questions before we take a guess at what is causing this.
- Does your truck smoke at all?
- If so, under what conditions?
- When the engine is at operating temperature and you go down a long hill, in gear, and then accerate does it smoke at all for a few seconds?
- How many miles since the last oil change? How black is the oil?
- When you start the engine does it turn over a lot before catching?
- Are you sure it used the oil? As this truck is new to you are you sure the oil was at the full mark when you started driving it? Suggest you fill it up and then monitor it.
- Did a mechanic check out the truck before you bought it?
- Was it bought from a dealer and is it under warranty? If it only has a 30 day warranty you had better get it back to them on Monday and record the problem before the warranty runs out.

 

I don't see the engine smoking at all. It has duals run straight out the back. But if it was smoking a bunch I think I would be able to see it. The oil doesn't seem too black. here is a thought what if the oil was changed with like 10w-40 that could make consumption go way up maybe? I talked to the previous owner who traded it to the dealership I bought it from and said it enver burned a drop of oil on him. Also my oil pressure seems fine 20 idle 40 load. Any ideas? What would an oil sample tell me

 

Welcome woolhauler, are you sure the dealer put 10w40 back into it, or maybe the 5w30 that some are useing. I'd also call the owner and ask the type oil that he used. To be sure and safe, I'd change it again, MYSELF, and use the oil that the earlier owner used and Fleetgaurd filter. 800 miles and 1 gallon of oil, it should be smokin like a tar kettle

 

Hey, let it sit for an hour or so to give the oil time to drain back into the pan. Or, you can just check it in the morning before startup. These engines take much longer to give an accurate level of the oil due to the engine holding so much more compared to a gas engine. I thought I had a problem when I first got my diesel with 206,000 on it. I let it sit for about an hour though and got the same reading for the last 2200 miles.
Chris

 

one gallon in 800 miles you should be seeing oil drippin out the tailpipe maybe if the dealer changed the oil, they didn't fill correctly. I would change it my self, correctly and then keep an eye on it. I have never added a drop of oil between changes on either one of these trucks ;D