overheating/heater not working

Old 01-27-00, 01:27 PM
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I have a 1991 Plymouth sundance. Well after a snow storm .I noticed the engine was running hot.I suspected the thermostat.I replaced the old and still the same.I was told to run the engine and take the radiator cap off to see if the anti-freeze was still or flowing. It was still! could this be the water pump or should I first try to flush the radiator out.Thanks for suggestions.
Old 01-27-00, 02:31 PM
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You've got one of Chrysler's poorest ideas: the cross flow radiator. The water circulates from left to right instead of up and down (like the older units) and, as a consequence, they plug up. Obviously, your coolant isn't circulating.
My advice is to take this machine to the radiator shop and have the radiator rodded.
Water pump? No, I wouldn't think this is a problem at this point. You will better know how it is doing after you get the radiator fixed.
Helpful hint: Buy one of Prestone's kits to put a hose connection in one of the heater hoses. This way, you can dump your fluid once in a while and back flush the system. While it is not a perfect solution, it gives you an edge on the problem. Use Prestone's 5-150 anti-freeze in the system and add one small can of water pump lubricant. Once you get things flowing again, these changes will make your driving a lot happier.
Sorry I didn't have better news. But, rodding the radiator is infinitely cheaper than buying a new engine.
Let us know how this turns out. We care about you folks out there.

Old 12-02-07, 11:56 AM
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Question 1991 Plymouth Sundance with a new thermostat and sporatic heat

Please help if you can! A few days ago, I was driving home and noticed I had no heat, despite my warm engine. By the time I got home my car began smoking and overheating. I drove immediately to the shop and had both my water pump and thermostat relaced.
When I picked up my car, the mechanic told me that my thermostat sensor was acting wonky and may need to be replaced.
Since then, the engine heat gauge has been bouncing from cold up to hot and back again every few minutes. This wouldn't bother me since it's clearly inaccurate, except that every time it goes up to hot, my heater stops blowing warm air and begins to blow cold air.

HELP! I can't make it through winter with no heat, but I don't want some mechanic to rip me off (possibly again).
Old 12-05-07, 05:03 AM
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Sounds as if the thermostat is defective, or he put in a 190 degree thermostat. I would try a 180 degree t'stat, which will open at the lower temperature.
Old 12-05-07, 05:42 AM
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I think you are low on coolant.
195 degree thermostat is original equipment.
Old 12-05-07, 08:55 AM
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Have your heater core checked out. it could be clogged.
Old 12-07-07, 12:04 AM
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There's always the possibility that the system wasn't bled properly after the new installation of thermostat. Make sure engine is cooled, and remove the cap, start the engine, and turn heater on. Let it run up to operating temperature, and watch for circulation in the rad & the fan should eventually come on. I've had some that will go through the circulation & fan cycle, 3 times before all the air is bled from the system. You will probably see bubbles during circulation. Try revving engine slightly every once in a while, for a few second at a time, to increase flow. Shouldn't be an airlock, if it's been driven & cooled off a few times, but it has happened.

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