Problem Description and Possible Solution
The upper intake manifold may develop an internal coolant leak causing one or more cylinders to fill with coolant. This can cause the engine to "hydro-lock" and not turn over. Removing the spark plugs will allow the engine to turn over pushing the coolant out of the spark plug holes. Replacing the upper intake plenum and gasket is commonly required to correct this condition.
The engine can be very difficult to start after this problem has been repaired, it can be helpful to clear as much of the coolant from the intake manifold and cylinders as possible before reassembling the intake manifold.
Problem DataRepairPal Verified
Average mileage: 151,619 (69,000–300,000)
Engine affected: 3.3L V6
18 people reported this problem
WATER WAS MAKING ENGINE MISS JUST BEFORE WOULD NOT START. ALSO HAD LOST LITTLE WATER AT A TIME FIRST.MOTOR SERVICE FIXED. ABOUT 250.00FOR PARTS AND LABOR JUST ABOUT SAME... SHOULD NOT HAVE TO PAY FOR CRACK IN PLASIC.....FACTORY MESS UP>>>>>>>> KENNETH BOYNE, CAR RUNS FINE NOW...
Just had the same problem with my son's car, $596 later to replace plastic upper plenum, seal, spark plugs, oil filter and oil change. Car would turn over but not start.
Same issue, coolant in the piston chamber, no help on a solution from GM. I'm in the process of a fix, probably need to get a new upper intake manifold.
My car is 1989, 300,000km, and from BC Canada. Last winter a o-ring near lower radiator hose developed leak. Car overheated and thought head gasket was shot. Before I got to fixing it car got to point it wouldn't start. Turned out to be hydro-lock. Could see slight bit of anti-freeze on side of the head so could assume that if it was hydro-lock which spark plug to take out. Car started really rough. Let it run for a bit and it cleared up some of the moisture. Turned off. Checked other plugs for moisture in the cylinders. When it comes right down to it we ended up just replacing the intake manifold gaskets and it's been good since.
At 95,000 miles I had this same problem. I replaced intake manifold cover. It happened again at 190,000 miles. The new cover has modification that should help. The standpipe that routs the exhaust gas through that area has been made smaller so that it does not touch the plastic manifold cover and thus keeping the intense heat away. You should stake the standpipe into the aluminum manifold to keep it in place.