Chevrolet Monte Carlo Problems

Intake Manifold Gasket May Leak Coolant or Engine Oil on Chevrolet Monte Carlo

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. Our technicians tell us that operating the engine  with a coolant/oil mix can result in internal engine damage. Replacing the intake manifold gasket should correct these leaks.

(109 people reported this problem)

Chevrolet Monte Carlo Vehicles With This Problem

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Average mileage: 123,350 (10,600–260,000)
Engines affected: 3.1L V6, 3.4L V6, 3.8L V6, 3.8L V6 Supercharged
12 model years affected: 1995, 1996, 1997, 1998, more1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007
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Viewing 1-20 of 44 comments
Engine overheated (x2) replaced rad/ thermostat. Water pump replaced 2 yrs prior. Installed aluminum manifold "elbows" instead of plastic. No visible leaks. Engine will start but rough idle and water flushes back into coolant overflow tank instead of into block making temp rise quickly
I have recall on my front valve cover and front valve cover gasket. When i took it somewhere they told me it was my manifold going out. So r those the same thing?
If you want to stop or prevent the problems you see here STOP USING DEX-COOL.
It was documented in 2007 that DEX-COOL was and still is the cause of the cooling system leaks and gasket leaks. Why you ask? Well to start with DEX-COOL has acid in it. Okay don't believe me, check on it your self. DEX-COOL is an O.A.T. type of coolant. Organic Acid Technology.
It is the whole reason for intake manifold gaskets leaking.
I you want to save money and aggravation flush your cooling system and use EVANS COOLANT. It is life time anti-freeze/coolant that has been used in all types of vehicles with no failures in cooling system parts. The main reason is with you DO NOT USE WATER with EVANS. No water means no corrosion and no cavitation which destroys water pumps. Also no water means no chance of freezing and no need to pressurized systems which makes your rubber hoses last much much longer.
I made the mistake of changing all six of my cars to DEX-COOL about seven years ago. Within three year half of the cars have problems with the cooling systems. I flushed the cooling systems, made the necessary repairs and changed my two classic cars to EVANS and the othe four cars got green Preston. Not one single problem since.
02 monte carlo ss the upper intake is leakeing water into the oil about the third time in three years .
Coolant leak from plenum at 65k, failed lower intake manifold gasket at 99k, failed again at 115k leaking into engine oil and ruining engine. Towed to residence yesterday. I'm going to have to part out a repainted, beautiful SS with a rebuilt transmission and lots of new parts, because I can't afford a rebuild. I hate GM.
I had this happen at 84,000 miles and again at 96,000. Both times the head gasket had to be replaced. I traded it in and the dealer said the same thing as the garage. Just too much nickle and diming to have it replaced again. I know things wear out, but ouch. Both times were in the winter, when you want heat pumping through the vents, not an overheated, leaking car.
This will be the 3 Intake and gasket replacement. First two the coolant was always low. This time oil is leaking on to the intake valleys and oil level is dropping. Plugs burn excellent.
1st atempt r&r all intake gaskets .worked 3weeks properly .then steam in exhaust after 6 months oil in exhaust stoped up convertor & h2o sensor r&r those parts to get running . 2nd atempt lot of coolant in oil pan 3rd atempt r&r all gaskets new lower &upper intake manifolds work in progress
Coolant leak was diagnosed as an intake manifold gasket leak. Antifreeze has not mixed in the crank case oil.
Around 37k miles I had over-heating and coolant problems. Then 48k miles I had to replace head gaskets. At 78k miles car over heating and replaced head gaskets again.. Now 120k miles coolant leaking again. Can't find sign of leaking so I think I'll change from Dex-Cool because of what I'm reading about it causing the head gasket leaks.
coolant leaking internal water in oil local expensive to fix was 627.00 and this was the 2nd time