Question about 1999 Pontiac Sunfire

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Low coolant light was going on and off...filled coolant...puddle of coolant under car...can't see leak anywhere. Head gasket was changed about a year ago...also replaced hose thought to be source of leak about a year coolant leaking again???

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  • CarySchroeder May 11, 2010

    Could be from many sources. Assume you have checked the main hoses. Is it from front or rear of engine compartment? Check: Water pump heater hoses radiator (this should be a leak in the front.) freeze plugs Is it a small leak or a large leak? Does it leak when engine cold, just sitting there, or only when engine running, engine hot? Does leak change when the heater is on or off?


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There could be a leak, to find out you must pressure test the cooling system. Also test the cap.

Posted on Sep 28, 2009

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Heated oxygen sensor heater control circuit low , also see below

the code is for coolant leak large. Check coolant level and top off.
check the oil for moisture.
pull the plugs to see if any are steam cleaned.
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