QuestionQUESTION: Hi Todd! I have a 97 Pontiac Grand Am GT, 2.3 twin cam, quad 4 with approx. 97,000 miles. Had big coolant leak & heater core was replaced about 10 months ago. Still going thru anti-freeze like crazy. Put another gallon in reservoir today. What's weird - never any puddles under my car. Have used GM' gasket seal tablets, as one mechanic told me it's the head gasket. Recently, if the car is low on anti-freeze, I don't get any heat, yet the car will overheat. As soon as I see the temp gauge going toward the "red zone", I pull over & shut the car off, but while I'm doing this, I'm hearing & feeling a thumping noise. My guess? Thermostat. What do you think?
ANSWER: Hi Sue:
Bad news sounds to me like a head gasket as well. if your no getting and laking onto the ground when the car sit but yet you going through coolant it's going somewhere either into the crank case or it's burning it out the tail pipe. both thinsg are bad. the noise you hear is the air in the cooling system collecting in the heater core and what little coolant that is in there is boiling. if this has been overheating for a while it more then likley damaged the cylinder head it could have either cracked or warped from the heat. With out seeing it it's really hard to say but from what your telling me it sounds like it started out as a head gasket and hopefully it has not escilated to something worse. pull out the engine oil dip stick and look at the oil if the level is hight and it is a white milk shake look to it for sure that is what happened.
---------- FOLLOW-UP ----------
QUESTION: So far, the oil looks good, although an oil change is due. I'm not getting any smoke from the tail pipe, just steam when I first start it when it's cold out. It just started the overheating a little over a month ago and doesn't do it all the time. Would changing the thermostat help any? I know it's in a bad place on my car - behind the water pump? So can I keep it "alive" by feeding it anti-freeze? What about the head gasket sealant tablets - good or bad? Now, does this mean the head gasket has blown? If not, what will happen when it does blow? I can't afford a car now. My husband and I are splitting up. Help!
ANSWER: It could be a thrmostat for the temp swings but I doubt it. more then likley the temp swing is due to low coolant and the thermostat doesn't work well when there is no coolant up against it. Yes they are a pain to change on that engine but back to the loosing coolant issue if it's not leaking it onto the ground and you don't see it in the engine oil then the engine is burning it and the only way it will burn it is if the head gasjet is blown or it had a bad cylinder head. "usually" ther is not an issue with the engine block that is cast iron the head is aluminum and much more likley to have dame to it from over heating.
---------- FOLLOW-UP ----------
QUESTION: Thanx a bunch Todd! Should I try & keep it alive by feeding it anti-freeze? What about the gasket sealing tablets? And last but not least, is the head gasket blown or about to blow?
Answerthoes seal tabs do not work for head gaskets. yes keep feeding it antifreeze but eventaully it's going to cause mechanical damage to the engine I can't tell you how bad it is with out seeing it but from the sounds of it it's on it's way to being pretty bad. I personally would not keep driving it untill it's looked at and fixed.
