GMC Suburban 1500 Problems

Intake Manifold Gasket May Leak Coolant or Engine Oil on GMC Suburban 1500

Problem Description and Possible Solution

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.

(21 people reported this problem)

GMC Suburban 1500 Vehicles With This Problem

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Average mileage: 173,742 (99,700–258,000)
Engine affected: 5.7L V8
8 model years affected: 1992, 1993, 1994, 1995, more1996, 1997, 1998, 1999
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Viewing 1-7 of 7 comments
Engine began over heating and could be controlled by cabin heat being blown on high. So replaced thermostat but noticed it did nothing and then water/coolant leaking from underneath. Service garage determined manifold gasket failure. Have not taken action as of yet since total engine replacement was advised. Very expensive to do so.
Began w/diagnoses of H2O pump in need of replacement...but grew to a leaking manifold gasket...which grew from there. The lower intake manifold was cracked while trying to remove the fitting for the heater hose. By the time this episode was over, the lower intake manifold was replaced with a used unit & Good gasket set, new $$$$ fuel spider, new water pump, quick disconnect for the heater hose, plus a potpourri of clamps and misc. And, the distributor cap was also chipped during removal, so, add that to the hopper, as well. I have driven the Sub 1600 miles since the repair. Checked under the hood, and the antifreeze receptacle, was EMPTY, again...and I do not know for how long!?! It may be the quick disconnect installed for the heater hose, for there is a small leak there, it seems...but it is going back to the shop this a.m.
coolant leak in manifold gasket, internal and external. Coolant in oil. Blue Devil did not help, Bar's head gasket fix helped a lot but did not seal the leak, which is rather greater as engine warms with heater of. I may have to replace gasket as you suggest.
Engine blew. Coolant in engine due to cheap parts (gaskets, etc) installed in that model year. Common problem that should Chevrolet have informed buyers of. If they had we would have been able to save engine.
Intake manifold gasket leaking coolant to exterior along front of both heads. Diagnosed location of leaks with cooling system pressure tester.