The intake manifold gasket may develop and external engine oil or coolant leak. In some cases, an internal coolant leak may occur causing coolant to mix with the engine oil. Running the engine with a coolant/oil mix may result in engine damage. Replacing the intake manifold gasket should correct this issue.Google+
Car Problem Reports
GMC Yukon Intake Manifold Gaskets May Leak Coolant or Engine Oil
GMC Yukon Problem
Engines Affected: 5.7L V8, Gasoline
Average Mileage: 158,435 mi (130,000 mi - 187,000 mi)
Visitor, 1998 GMC Yukon, 187,000 mi
Noticed coolant leaking on driveway. Seems water pump has gone bad and is leaking through weep hole, and then noticed also apparent coolant leaking from intake manifold gasket leak...so both need to be fixed. Dealers estimate $500 for pump and $900 for intake manifold gasket. Would like to do it myself it that is feasible. Anyone know how?
Visitor, 2000 GMC Yukon, 130,000 mi
Have a 2000 yukon xl that has been leaking oil for awhile. Unfortunately, the water pump went out on me, and after pulling the water pump out, found oil all over the front of the engine. Not sure if it is leaking out of the timing chain cover or maybe the front main seal. Anyone know how difficult it is to replace either one of these gaskets/seals?
Visitor, 1996 GMC Yukon, 5.7L V8, 174,000 mi
GMC Sierra would heat and cool well most of the time, and there was no tint of blue smoke in the exhaust hinting at bad oil rings. However, it would always use oil "somewhere" and coolant too. This was our NORMAL for a couple years, then it dumped all of the coolant one day and the whole front of the motor was wet, including the water pump, so I assumed a bad pump seal, and replaced it. A few days later, my wife informed me that it was spewing out coolant again, and I tried to locate the source, but couldn't find one. Tried coolant leak stop and it worked for about a year, then we had the same problem again. So I did some more sleuthing, and googled "mystery coolant leak Chevy truck) and found the culprit. A cracked intake gasket. Vortec engines will all eventually develop a crack in their intake gasket coolant passages, and some will hold coolant until a certain pressure is obtained, usually while you are driving, so you can't observe it, then leak like a sieve. I pulled the intake( no need to pull the upper half off, just take out the 4 bolts on each side of the lower intake manifold, and mark and pull the distributor, and you can get at the gaskets. There was my crack, and leak, behind and underneath the alternator, where I couldn't see it unless it was happening. That's why the front of the engine was full of coolant. the gasket was also sagging down int he middle where the oil could be sucked into the engine in just enough of a quantity that it would be using it, but not enough to burn blue. Two problems solved.
Visitor, 2001 GMC Yukon, 160,550 mi
Leaking antifreeze fluid from manifold and / or head gasket. Thought it was the water pump. Fluid would leak while engine was on or if had been on, but not while just sitting.
Visitor, 1996 GMC Yukon, 5.7L V8, 140,000 mi
had a slow coolant leak that got worse until the gasket blew.
Visitor, 1996 GMC Yukon, 5.7L V8, 177,500 mi
antifreeze drain problem have no idea what to do i just keep feeding it more i dont want to fix it.....
Visitor, 2000 GMC Yukon, 140,000 mi
Had that problem with oil leaking into the coolant. It was easily fixed by adding AC Delco Cooling System Seal Tabs (10-108 or 12378255). This product was develop due to a defective design in the North Star engine. The package comes with five tabs. Crush the tabs and add them to the coolant reservoir whenever there is a change in coolant. Keep extra tabs on hand because when coolant is added, there may be a drop in the coolant over time and so it would be necessary to add only a tab or two.
Should this problem in a GMC Yukon built in this era (2000 thru 2006) surface, the use of the cooling system tabs is an essential component of coolant maintenance.