The intake manifold gasket may develop an 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.
Car Problem Reports
Chevrolet Suburban 1500 Intake Manifold Gaskets May Leak Coolant or Engine Oil
Chevrolet Suburban 1500 Problem
Engines Affected: 5.7L V8, Gasoline
Average Mileage: 128,437 mi (41,000 mi - 207,212 mi)
Visitor, 1994 Chevrolet Suburban 1500, 106,000 mi
When I checked the oil (only 200 miles after oil change) I found an over full condition and the oil was milky colored. I then checked the radiator and the coolant was low. I pressure tested the radiator and it held pressure. I then changed the oil and filter and ran the engine to operating temp, with the engiene running and radiator cap removed I looked for bubbling in the radiator that would be common with a blown head gasket, there were no bubbles. I replaced the radiator cap and let the vehicle sit over night then checked the oil, it was over full and milky colored and coolant was down again. I concluded it was most likely an intake gasket by the amount of coolant in the oil. If it were a head gasket most of the coolant would likely burn off while the engine was running. I pulled the intake manifold and looked for the leak path in the gasket, also checking for a crack in the lifter galley of the engine block. The block looked good so replaced the intake gasket and all is well so far, clean oil and full radiator.
Visitor, 1999 Chevrolet Suburban 1500, 5.7L V8, 140,000 mi
uses extra coolant. still looking for a cure.
Visitor, 1995 Chevrolet Suburban 1500, 5.7L V8, 47,000 mi
Coolant observed pooling on the intake manifold where it meets the head and in front portion of engine block/intake manifold weeping of coolant seeping there too. A temporary band-aid fix is what I used until the intake gasket was replaced; the band-aid was accomplished by adding Bar's-type stop leak for radiators. It is Irritating that GM would not make this right via recall. Mechanic charge was $500 to replace the intake manifold gasket.
Visitor, 1999 Chevrolet Suburban 1500, 5.7L V8, 150,000 mi
My suburban started leaking coolant a few years ago. A mechanic said it was the intake. I kept driving it until the coolant started mixing with the oil in the engine and the vehicle started running hot. I have a mechanic working on it now who says he may be able to repair the intake valve without replacing it.
Could smell hot coolant and noticed small leak when checking oil level
leaking water finally researched and realized that it is a frequent issue.
Visitor, 1998 Chevrolet Suburban 1500, 5.7L V8, 150,000 mi
leaking coolant due to failed intake gasket. Had to have intake gasket replaced.
flused coolent system with CLR and a month later while driving I noticed the temp gauge beyond 210, the it dropped back down to normal. I then checked my antifreeze and it was full.the next day I checked and I needed to add antifreeze.I checked the oil and had this milky substance on the dip stick. I also checked the oil cap but didnt have now of the milky stuff inside the cap. After 5 mins of running steam start to become visible...is this a head or intake gasket failure?
Visitor, 2002 Chevrolet Suburban 1500, 115,000 mi
oil is leaking in engine compartment
Visitor, 2004 Chevrolet Suburban 1500, 41,000 mi
started losing coolant took it to the Chevrolet house and they could not find anything wrong. Paid for the diagnostic work. Went back and forth to Chevy house and on the fourth trip they said it was the water pump, I said fix it. The coolant lose stopped for three month and then started up again. on the fifth trip to the chevy house they said i had a cracked head. I asked how and they said I overheated the vehicle, which I informed them that was not the case and told them to check the computer codes. The Chevy house asked if i had an extended warranty, which I did. the Chevy house wanted my extended warranty company to pay for the repairs and the extended warranty company wanted chevy to pay. the chevy house finally paid for the repairs. After getting the vehicle back and driving it for three months it started loosing coolant again. I chose to drive it and add coolant as needed. at 108000 miles I had the engine rebuilt. the coolant lose stopped and after three months it started again. This is a well know problem on 2004 chevy trucks/ suburbans and gn will not do anything about. I will drive it as long as i can and then put a crate engine in it. hopefully that will be the end of the coolant lose.