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Discussion Starter #1
My 1997 mustang is overheating at low speeds or if I run the a/c at the coldest setting. Without the a/c runniing it will overheat if I run below 50 mph. At 55+ it stays in the middle of the guage all day long. If I turn the a/c on at the coldest setting it will overheat within 10 miles. If I back it down 2 clicks from the coldest setting it will run ok as long as I am driving 55+. At three or more clicks from the coldest setting it runs close to normalexcept at idle, it will overheat! Has anyone had a simular problem that can direct me in what direction to proceed? I was loosing water until about 20,000 miles ago, I changed the water pump and gaskets. I still loose water but not at a high rate.
 

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sounds like a head gasket has been blown to me. has your car been in for the head gasket recall? Check your oil if it looks "milky" then it is your head gasket for sure.
 

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" I still loose water but not at a high rate."

It's gotta be going somewhere. If your oil is not milky then very carefully see how much pressure is in your radiator when hot. Also look at your coolant, you may see signs of the oil getting into the cooling system, it will have some goo around the inside neck of the radiator.

Goog Luck
 

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The engine runs fine with no oil in the water or water in the oil. It does not smoke out the exhaust or push water out the tailpipe. There may be a small leak around the water pump but I only put 1 gallon of water every 3 or 4 weeks. I run about 500 miles per week back and forth to work. I did take it to Orlando a month ago and it ran perfect all the way there, with the a/c at the coldest setting. When I pulled in and parked it started overheating.:eyebulge:
 

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have you checked the thermostat, if your fluids are fine I would go ahead and replace that. with a 160 degree thermostat.
 

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lcurle said:
have you checked the thermostat, if your fluids are fine I would go ahead and replace that. with a 160 degree thermostat.
No!!! don't do that!!

It works on old 5.0L cars but it will give your computer fits in the 3.8L and will actually harm the engine!! 180 is the lowest you can go, and you should reprogram the computer to accept it.

THe head gasket can fail without it going into the oil.

Run it in for a pressure test, one of your hoses may be collapsing.
 

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This is the same problem with my newly aquired 97. Runs perfect and doesn't get hot until you sit with the motor and ac going. Start moving, get on the freeway and it comes right back down. Just like the fan isn;t pulling enough air. It's on R most of the time, then into the A when getting hot. I let it go while sitting(extended sitting time) the other day and it didn't go any higher than A. I've had the car for about a month now, oil is crystal clear. Other than the timing chain cover leaking a bit it doesn't take much water. I'm sort of stumped to. Going to go down to a 180 when I do the cover, That radiator is a cheap 1.2 core job. It could probably use a bit bigger one.
 

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The thermostat doesn't make sense to me. Why would it work fine without the a/c running and fail everytime the a/c is turned on. one of the hoses collapsing sounds like it might be a problem. Same hoses that came on the car. the car is over 5 years old with about 150,000 miles on it. thanks for the info. :worship
 

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had the same problem with mine over heating, except i can't remember if the a/c was involved. I replaced the fan clutch-no change, replaced the termostat-no change, replaced the hoses-no change, and then i replaced the cheapest part of all, the radiator cap and problem gone. runs right in the middle. The cooling system is pressurized and the spring in the old cap becomes weak and will lose pressure when you stress it. Try it, only cost about 5 bucks and if it cures the problem you can replace the hoses later.

Jon
:drink:
 

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rcarrsr said:
I only put 1 gallon of water every 3 or 4 weeks. :eyebulge:
Mine was the same way and I figured that 1 gal every 3 or 4 weeks was not bad either. When it got to 2 gal a day I changed the head gaskests :winks
 

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Fan ?

Did you check if your radiator fan is working at high speed ? This fans has two speed and when temperature raise it must switch to high speed. In mine this was the problem. When the car is overheating just run out and check if the fan work. If not, there is your problem.

BTW, the fans also switch to high speed automatically when you use A/C.
 
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