I have a 1992 Plymouth Sundance with 130000 miles. 4 cyl, 2.0L It has been well taken care of with regular maintenance between 3k to 5k intervals since I bought it with 58k. The car instantly overheats when turned on. The heat blows frigidly cold air. It has a thermostat that is ~5 months old. The car will shudder and shake and then cut out when left idling or when it over heats. It is not losing coolant, but the car smells like burning antifreeze when you lift the hood. It will also steam and or smoke that escapes from under the hood when you turn it on. 1.) What are the possible diagnoses? 2.) How much will it cost? (Chicago area) 3.) Is it worth spending the money on a rebuilt car that I've had since high school, or should I just give up and buy a newer car? The most common cause of simultaneous engine overheating and no heat from the heater is extremely low engine coolant level, in other words a large pocket of air in the system. In some cars it's fairly easy to get the air out, in others it's very tricky. If there's a leak causing coolant loss, that will also have to be addressed or the problem will recur/worsen. Check 1. Your Thermostat (70%) of the time it is your thermostat. 2. Check and see if your radiator is clogged (Also very common).
Another issue is if your car overheats during idle, then it could be the electric radiator fan.
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A leaking heater core will cause the engine to overheat because the coolant is leaking out.
water pump may not be worn out, heater core may be clogging
It could, but I'd start by checking the timing. If it's off the car will overheat, and that's easy to adjust. Heater cores are a grade-A pain to replace because you have to take apart the dash to get to them.
No
No, a clogged heater core will not make it overheat. A leaking heater core will.
Typical of the heater core leaking. Overheat because of low fluid and pressure. Foggy windshield due to heater core leaking and will smell antifreeze in the car.
Try changing the themometer
Not necessarily. It depends on what you mean by a bad heater core. The core will either be leaking or stopped up. If it is leaking, then it can cause the engine to overheat and the only fix is to replace it. A clogged or plugged heater core can sometimes be fixed by flushing it. You can also temporarily bypass the heater core until you can get it fixed. Just connect the inlet & outlet heater hoses together.
You should check your water level. It's low, and you have a leak. Get someone to check it for you. The heater in your car works off the water from your radiator, no water in the radiator will over heat the engine ergo top up the water. Could also be low antifreeze level causing water in radiator to freeze making the engine overheat and the heater to blow cold air. You have an airlock. If you have a system with expansion/filler tank then check the return pipe is not blocked. These systems bleed themselves if there are no blockages. Mine was because the impeller in the water pump had disintegrated to the point where it would not move the water. The water would overheat, but the hot water would not get moved into the heater core to blow hot air. I replaced the water pump and it all works now.
either the thermostat or the fan is no good. You would need to locate the thermostat and see if its stuck open or closed!
thermostats problem my car did the same thing when mine went out
generally if an engine overheats, but then does not overheat when heater is turned on, is a good indication that the engine thermostat is stuck and needs replacing