2003 GMC 2500HD Oil Problems

[BigBlockMike]

My 2001 8.1 did the same thing. That motor consumed a good bit of oil. A shop teacher at the high school I went to had an 03 2500hd with an 8.1 as well and he said that it consumes oil as well, and his truck has real low miles, so it seems to be a common occurrence with 8.1s.

 

[4x4chevydude]

I would reccomend a high mileage oil in 10w40 get some thicker stuff in there...the car companies were pressured to reccomend the thinnest oil they possibly could to improve fuel economy..so while the 5w30 may have worked for a while i think now the most appropriate would be a 10w40 or even a 5w40 if you could find it

 

[Smokefan1977]

GM 8.1's consumed oil plain and simple. I have built a couple of 8.1's that were consumers and now burn a qt in 5k. The 8.1's I have had apart I could move the piston around in the bore. The bore still had crosshatch in to.

New bore, KB pistons and total seal rings, valves, seals seemed to have helped. Both engines had over 100k on them when torn down

 

[SteveSRT8]

Big block Chevys are loose as a goose. They need a hard break in, if they don't get it they use oil. Run the pants off of them when new and they don't use any at all, or at least between the short OCI's we used to use.

BTW, adding a catch can will condense more out of the line than ever got into the intake before. It is MUCH cooler and thus many vaporized components are distilled that would normally have had no traces found.

You can put a catch can on anything with a crankcase and you'll quickly fill it. The only question is did you really need it or not.