Oil Consumption C-15

My 3406E 5EK when I down one gallon its usually time for service and thats about 12,000. I think your in good shape.

 

I drove a c-15 cat 2005 for seven months. It drank a galloon every 12,000 miles.

 

My c-15 will use that much oil between services been that way since new so your all good there. But 800k is getting up there on the miles, if he hasn't done much with that motor you will be. Top end, main and rod bearings, turbo end play, excessive blow by, and other things of that nature should be on your mind with those kind of miles.

 

My C-15 about the same, I usually change the oil around the time it needs a gallon at 12-15k. As far as having 800k it, get an oil sample, a good cat should get well into the million mile range. Plenty of cats that see the 1.5m mark. good luck

 

Yeah good call man. If nothing internal done on motor you can bet you'll be doing an in-frame in the near future.

 

As others have stated I would not be concerned about the oil use, sounds good especially for that many miles. As far as the wheel seals that is not an expensive fix. Also if a truck has set for a while it is not unusual to have to replace some wheel seals when putting the truck back in service.
Not saying to buy the truck, just that what you have said so far would not be a deal breaker to me. Depend on the price and the rest of the condition of the truck.

 

put it on dyno before you buy it .