Mechanics

ENGINE OVERHEATING

1999 Oldsmobile Alero

Engine Cooling problem
1999 Oldsmobile Alero 6 cyl Front Wheel Drive Automatic 118000 miles

i recently have been having overheating problems with my 99 oldsmobile alero with the 3.4 v6 engine. I have changed the thermostat, radiator, waterpump, all of the hoses, the overflow resovoir cap, . The fans work, the car overheats as you drive it really soon, when this occurs I pull the upper hose on the thermostat housing and oly steam comes out instead of coolant, there is no white smoke from the exhaust and the oil stays clear and clean. The heater does'nt blow hot air either. Do you have any suggestion as to what the remody to cure this would be? Thank you.
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Budgirlsam63
April 30, 2009.




Ok can you get the radiator full? Does it still overheat even then? I am thinking either an intake gasket upper intake plenum itself or head gasket. I need you to call around to you local shops and find one that does a chemical test to detect exhaust gases in the radiator. This test will tell us weather or not there is a head gasket problem. Let me know how it goes and what you find there. If the test comes out good then I would a pressure test and check for leaks in behind the throttle body. These plastic plenums crack in that water jacket there and feed anti freeze into the engine and it burn is off. If that is good then it may be an intake gasket problems. Hope this helps. Thanks and let me know what you find.

Racefan966
May 1, 2009.
I had same problem; replaced the coolant temp sensor, thermostat, and reservoir cap. Didn't help. Turned out that the plastic reservoir itself was slightly warped/out-of-round where the cap screws in, so that even with cap on tightly it would not hold pressure. To test this, I put the black overflow hose that comes out of the reservoir (near the cap) into a clear plastic water bottle. With engine hot and a little water in the bottle, I could squeeze the radiator hose and see bubbles in the water bottle. No air or coolant is supposed to get through that cap until it's over 15PSI. Got a new reservoir ($35/RockAuto) and now system holds pressure. I'm leaving the plastic bottle in place, the overflow hose sort of holds it in place, doesn't interfere with nearby moving parts, and will show me if there's any more overflow (haven't seen any in 3 days)

Tiny
Skeeter
Jul 8, 2009.
I am so glad I read the reply from skeeter. My sister's 1999 Oldsmobile Alero was pumping all of the fluid out of the reservoir and of course over heating.I did the water bottle test and sure enough the reservoir was bad. Everyone was saying it was a blown head gasket. New tank and coolant for about $55.00. Thanks for the great information.

Tiny
AndrewAiken
Aug 5, 2011.
Great glad to hear it.
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Racefan966
Aug 13, 2011.

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