Include

[Njellison]

Originally Posted by 6.9Laska

i have a 6.9 1985 uses about 4 quarts of oil every 100 miles no leaks burns it.
idk whats causing it i checked CDR valve and it ok there is no oil in the intake this problem just popped up outta nowear
anyone ever run across this before?
thanks

OK.... not good. I agree that overfill can cause excess oil to be burned but cannot imagine this much. Are you topping it off every 25 miles or did you check it at 100 miles and have to add 4 qts?

CDR valve is also likely oil siphon culprit but you indicate not bad.

Let's assume you are blue smoke all the time with this much oil being burned, if not then you are leaking it. Have someone drive behind you , or better yet have someone drive your truck and you drive behind them and get an idea about how much is burning.

How much puffing do you get from the oil fill cap when removed? If major locomotive pulling a hill type of puffing then rings or head gasket are probably to blame.

I go through about a quart every month or so (500 to 1000 miles), some leaks (rear main) and some burns as is evident by the light blue smoke at start up and minor smoke blow out the oil filler when cap is removed. This is typical for the rigs I have seen. What you have is not typical. Good luck and let us know what you find.