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.
Problems for specific Chevrolet G Series Van (G30) years:
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Most reported Chevrolet G Series Van (G30) problems
A coolant leak may develop from the water pump. This can result in an engine overheating condition. A leaking water pump will require replacement.
An engine vacuum leak may develop from the throttle body gasket causing a higher than normal idle speed. Failed gaskets should be replaced.
On the 4L80-E Transmission (Diesel and 7.4L gas engine), Transmission fluid may leak through the electrical connector on the side of the transmission, damaging the wire harness and causing the transmission to shift erratically. Our technicians tell us there are updated shift solenoids, an internal transmission harness, and a connector pigtail available to correct this fault.
The engine may develop a misfire due to worn valve seats. This fault will cause the Check Engine Light to illuminate. Our technicians tell us the misfire may or may not be felt while driving. They further recommend that both cylinder heads be removed and thoroughly inspected and repaired as necessary.
One or more fuel injectors may become stuck closed causing an engine misfire and the Check Engine Light to illuminate. Our technicians tell us that this problem can be caused by some fuel additives. There are special procedures which may be able to restore the affected injector. If this fails the affected injector must be replaced.
A loose or worn gas cap could be cause the Check Engine Light to illuminate.
I had a mysterious leak of coolant. It was winter and I was losing coolant. I could fill the coolant up drive, forever w/heat on and check the coolant and it was fine. I would check the coolant before starting the truck and it would be half empty.
I have the habit of turning everything off in the vehicle before turning off the car, especially in the winter when I know it is hard to start in the AM. I turn off the heat.
The heat control valv...