# 1999 Malibu 3.1L overheating



## kf4ayw (Apr 14, 2008)

This thing is driving me crazy. My son has a 99 Malibu and it has overheated on him several times. The last time was 200 miles from home and caused the premature death of an engine. Just replace the entire motor this weekend. Water pump looked good and new thermostat. The car does not actually overheat going down the road, but when you sit idle for an extended period of time or shut the car off after being on the road it will boil water out of the overflow, which will eventually drain the system.

Any Ideas? I haven't a clue..... This is the same problem that was happening before the other motor died. I need help. 


Thanks in advance... 

Michael


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## manic (Aug 2, 2005)

Does that have a electric fan? If so is it coming on when its 
supposed to? What condition is the radiator in? Are you using the
same water pump as before? Take a compression test on each
cylinder, maybe a warped head, aluminum head will warp real
quick..


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## BUDFAN8 (Apr 11, 2007)

i believe manic is right your electric fan is not working there should be a relay for it somewhere. check your manual and replace the relay if the fan still dosent come on could be wireing or the fan is no good.


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## jinfei (Apr 16, 2008)

try checking on the radiator host if its ok, try the wirings of the auxiliary fan. maybe it reverse the spin of the aux. fan


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## pt121984 (Mar 21, 2007)

Along with making sure the electric fan is working properly, some of the 3.1 engines have a bleeder valve on top of the water outlet to enable you to bleed air out of the highest point of the engine. Not entirely sure yours does, but check to make sure. 

Patrick


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## BUDFAN8 (Apr 11, 2007)

good point patrick. if the coolant system wasnt bled correctly when the motor was installed, it would still overheat.


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## kf4ayw (Apr 14, 2008)

Thanks for all the comments.


On the bleeder valve, how do I know when it is complete.


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## bruiser (Jul 30, 2005)

When you open the bleeder valve(s), air and bubbles should hiss their way out if air is present. When coolant begins to flow out of the valve, close it. When engine cools down, check the radiator and add coolant if necessary. You may need to repeat this a few times as some air pockets are very stubborn.


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