QuestionMy 95' Intrepid is overheating. It is cold outside and it has a brand new radiator in it that was just put in this summer. It has antifreeze in it so it is not frozen, but there is no heat coming out of the heater either, just cold air. The temperature gauge starts going up slowly but then all of a sudden it goes up very fast and it starts to over heat. I just put a new motor in it last year around this time. I also had a new heater core put in last year. I even tried pulling out the termostate to see if it was sticking but it is not so it is not that. Please explain in easy terms I am a woman and don't really understand car language. Thank You.
AnswerHi Stacey,
There are several possibilities. First you need to verify that the water pump drive belt has not broken and therefore there is no circulation of water in the engine and to the heater. But with either the 3.3 of the 3.5 engine the belts are so crucial that if one broke there would be more wrong than just the water pump. So this is probably not the issue though the pump itself could have a loose impeller and thus not circulating the water. You could look in the filler neck when the engine is idling to observe that water seems to be moving down below, but only do this when the engine has just been started from cold so it isn't overheated and pressurized.
If the temperature shoots up and there appears to be the possibility of coolant being discharged from the overflow bottle if you don't turn it off, or you have had steam or water discharged, then there could be a head gasket leak on one of the two cylinder heads of your recently rebuilt engine. That would manifest itself as milky oil in the crankcase, alot of white smoke coming out the exhaust pipe, or a rapid pressurization of the cooling system with discharge from the overflow bottle. Any of those symptoms or a test for exhaust gas in the system by putting a sensor in place of the filler cap (done at a radiator shop) would tell you for sure if this is the cause. The heater would not work well either if this is what is going on because of the internal steam would compromise the coolant flow throughout the system. I hope this is not the reason, but if so perhaps the engine repair is still under warranty.
The radiator fans may not be coming on when required to do so, so check that when the temp gauge runs toward hi. The fans should come on. If not then the fans or the sensor for the fans or the relays are the problem.
If you haven't lost coolant, nonetheless there could be air trapped in the system which is impeding the coolant flow to the radiator and the engine. Was there any concurrent work done on the system just before this started, such as draining and refilling it? If so that might be what is causing the issue.
You have seen that there is coolant about half way up in the overflow bottle when the engine is cold, correct? If not then you may be low on coolant which is why you are having the overheat/no heater. Any leakage of fluid noticed?
These are some of the possibilities/observations that may be helpful in figuring out the reason.
Let me know if any of these rings a bell.
Roland
