Overheating on 91 Explorer

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Nov 8, 2003 | 09:39 AM

dmarple

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Joined: Nov 2003

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Overheating on 91 Explorer

Hi folks

I have a 91 explorer that indicates that is is running hot whenever
I turn the A/C on. It does not seem to matter whether I am running at low speed or high. Low speed + no A/C = cool
highspeed + A/C = hot.

Any ideas ?

Thanks

Dennis

Nov 8, 2003 | 05:16 PM

golfboy17

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Joined: Sep 2003

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The AC ussually generates heat when its going but the vehicals cooling system handles it so you really dont notice. Now the Over heating can be due to simply your low on coolent, check the radiator and the tank, when the engine is cool and make sure they are both full on the tank to the full cold line. It could also be the T-stat which is a cheep and ez fix, to check this let the engine warm up, and feel the upper radiator hose if its hot, then its probally not your t-stat if its cold then your t-stat is stuck open replace it, and if its not that it could be the water pump, have you been noticing any leaks? Look around the water pump and see if you see any collent around it, if its your water pump i would replace the t-stat as well, and if its not that it could be there is a block somewere in the radiator, and finally if its not that, and you have an auto trans, then that could be malfuncting causeing the engine to overheat, I wish i could give you one answer but with the cooling system there are several possibilitis...GOOD LUCK

Nov 10, 2003 | 07:01 PM

bikesrfun

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Joined: Oct 2003

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Check the radiator. After a few years deposits build up in the radiator and collect in the cooling tubes which limits the coolant flow. This reduces the dissipation of heat which will make the engine run hotter especially when the a/c is on and the condensor is also trying to dissipate heat (in front of the radiator).
If you can remove the top hose and look inside with an inspection mirror you can see the coolant tubes and if there is a white deposit around the inside diameter of the tubes the radiator needs to be boiled out or replaced.