04 Duramax Possible Oil Leak. Help!

C6Racer · January 11, 2009

Hi all. Today, I found something rather discomforting. My dad has a 2004 Sierra K2500HD with the LLY DMax with 142,000 miles on it. It had been pinging like crazy under light throttle. I had the PCM scanned and retrieved two EGR codes for insufficient EGR flow. If I tapped the EGR motor with the handle of a hammer, the pinging would stop for a while, so I was sure the valve was getting stuck. There is A LOT of sludge-like build up at the base of the EGR motor and the clamp of the turbo outlet. I proceeded to remove the EGR valve(pain in the ass) and was shocked at what I found. The passages of the tube that sits on top of it, and of the valve itself, remind me of badly clogged arteries except it's black. There is a crap load of oil-soaked carbon build up. The tube leading from the exhaust down pipe to the EGR valve has some dry carbon build up. The EGR valve has a little hole under it and there is oil leaking out of it onto the front of the RH valve cover. It looks like there is oil leaking from the intake side of the turbo. Could this be?

If so, I have a few more questions. Is the turbo rebuildable? As in, would a DYIer be able to take it apart and replace the seals, assuming the bearings are still in good shape? If not, does anyone know where, and for how much $, I can get a good deal on a new or rebuilt turbo?

Thanks guys and sorry for the lost post. I like giving as much info as possible to reduce the amount of questions -Lorenzo

markw8 · January 12, 2009

It was mentioned by a tech at a Corvette site, talking about letting diesels idle, that the D-max was prone to carbon up the EGR system. This doesn' answer your question, but maybe useful info.

Mark.

C6Racer · January 12, 2009

Thanks for your input, Mark.

Well, yesterday I started the process of getting to the turbo to remove it when I stumbled upon a hose that I thought was for coolant, but it turned out that it is a PCV hose. I found that to be the source of the oil in the intake system. I thought thank GOD it wasn't the turbo. It seems to be letting too much oil getting into the intake, but it doesn't come with a PCV valve. I guess I'll just have to replace the EGR valve every 140k miles.