So I checked the oil level in the new truck and the oil is about an inch above the safe mark. Is this overfill common or OK for the Cummins, or should I drain a bit of it?

Thanks

 

Is it normal, I don't think so. Might want to run it back by the dealer if you just bought it. They might want to make sure all the injectors are ok.

 

There is a tendancey to over fill. I would drain off to the correct mark. Make sure your truck is level. Having it too full can cause excessive oil to come out the breather tube. I'm not sure where it is on an 06, but it can cause a mess.

 

I just had dealer do first oil change, and when I got home I checked and sure enough, oil level is a little (1/4 to 1/2 inch) above top hash mark on stick. In a gas engine I'd be worried about blowing a rear main seal this way, but from what I can tell, no one seems too worried about that sort of thing with diesels.

So I guess I'll not sweat it - I don't have a real opportunity to get rid of oil so not excited about draining a little off.

 

Not too worried about slightly over opn my gas burners eaither.

 

You might check the manual. Mine says to check the oil 15 minutes after you shut it down. I do that on mine and it is right at the full mark. If I wait until an hour or so goes by or all night it reads about a quart over full. I think that oil drains from spaces that are supposed to keep oil in them and that is what gives the over full reading.