2004 gmc 2500hd lb7 duramax! Coolant/oil in exhaust!

[hinton08]

Recently put a new long block in a 2004 GMC 2500HD with an LB7 Duramax due to bad rings and burnt piston. Got everything back together. The vehicle runs now but after a minute or two, it begins to smoke a little out the exhaust. There is a hole in the muffler and oil/coolant started coming out of the hole. It looked like coolant was in the oil by checking the dipstick as well. I thought maybe coolant had gotten into the exhaust pipe when I disconnected the turbo pipes so I changed the oil again. After starting the vehicle and giving it a little gas, same result. Could it possibly be the turbo seals going out? I dont understand why it didnt do it before though. Any help is greatly appreciated!

[consultIII]

sounds like head gaskets. typically with bad head gaskets you would get combustion pressure into the cooling system/ coolant reservoir. You could test the coolant for combustion gases with a jobber kit. You could put a coolant pressure tester on the cooling system and run the engine...be ready to shut off the engine as the pressure could build fast.

[hinton08]

It was just coolant in the muffler from when I removed the old engine. I took it out and blew it out on the interstate and it runs fine now.

[consultIII]

was thinking maybe egr cooler but you already figured it.

[hinton08]

There is no EGR on this engine

[consultIII]

a stock 2004 6.6L lb7 duramax has a vacuum controlled egr valve, egr cooler and egr vacuum pump.

[hinton08]

where is it at on the engine?

[consultIII]

just above the passenger side valve cover. If you look from the front; between the air cleaner duct and the map duct you can see the black connector for the valve. rearward is the cooler with a hose running up to one of the thermostats. tried to get you a picture but would of have to remove stuff for a clear view.