There is a common problem with these engines. They (NaPa) actually sell a kit to repair it. It is from the EGR port that comes out of lower intake manifold and vents into the UIM by the throttle body. The tube deteriorates and the coolant leaks into the lower manifold and mixes with oil. I did the job in about 3 hours, in my driveway. There was a guy on here that had a step by step diagram of the whole job. The kit I bought had the new tube and a whole new upper plenum with all the gaskets included. You have to remove the throttle body, fuel cage with fuel injectors, upper intake plenum, and vacume lines. Grab a pair of vise grips and rip the old tube out then tap the new one in with a little persuasion. You can leave the fuel cage in tact and just tie it up out of the way. Good Luck
Rob
