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Discussion Starter #1
Hey Guys,

Lately it's been getting hella hot here in Cali and I noticed the other day that the temperature gauge creeped up on an especially hot day, (upper 90's). Of course I had my A/C on. Normally my car sits with the temp needle right in the middle, (let's call this 50%) at all times. If it's not super hot out I can run the A/C without any issues. But on this day the needle crept up to about 75% while driving in traffic. When I turned the A/C off the temp went back to 50% after a few minutes.

Last weekend I bought some Water Wetter and added a whole bottle to the radiator. Yesterday again it was high 90's and I noticed that even at freeway speed with the A/C on the needle went up to 75%. Again I turned the A/C off and the needle went back to 50%.

The fact that the temp will go up even at freeway speed has me concerned. I searched around and saw many recommendations for the GT500 fan. But shouldn't the air blowing over the block at speed be enough to cool the engine?

By the way I don't see any coolant leaks. Also I looked at the front of the radiator and there are some fins that have been bent but I wouldn't think enough that would hamper cooling that much.

Any suggestions?
 

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airflow isnt the problem obviously your radiator is clogged with road debris

this is more common on the panther vehicles were the radiator has to be removed from the condenser and cleaned every few years.

You probably have a bit of debris blocking the radiator.
 

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Discussion Starter #4
Unless the debris is behind the radiator I didn't really see anything when I looked at it yesterday.

But I did notice today that when the car was already warmed up after driving for a bit and being parked, I started it up and the fan immediately came on. I then turned on the A/C because I read that the fan is supposed to turn up to high every time the A/C is turned on and it didn't. It stayed at the same speed it was at.

Maybe this is the problem? The fan is not turning to high when the A/C is on and the extra heat from the condensor is not getting drawn away like it should?
 

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Discussion Starter #8
I took the car to a local shop today and they verified that the fan is not turning on to high mode. Is the controller/fuse/relay that handles this part of the fan or is it somewhere else? If I replace the fan with the GT500 fan is that controller part of the fan?
 

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Discussion Starter #12
I tried replacing both fan speed relays. Today I tried starting the car cold. No fan. Then turned on the A/C with fan speed on 1 and the fan came on at the low speed I guess. I turned the A/C dial all the way up to 4 and no change to the radiator fan speed. Just in case the fan was spinning faster and I just couldn't tell I measured the airflow with an anemometer and got about 6 meters/second either way.



What else might the issue be?
 

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i just said the blower speed has no input to cooling fan speed

high speed is initiated by a switch, sensing the refrigerant in the line

do you see that in the wiring diagram?
 

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Discussion Starter #14
i just said the blower speed has no input to cooling fan speed

high speed is initiated by a switch, sensing the refrigerant in the line

do you see that in the wiring diagram?
What diagram are you referring to?
 

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Your first post says that it overheats with a/c on at freeway speeds

You can diagnose high speed fan, but that will not be relevant for highway speeds

The fan is turn off completely

One problem could be that the fan is on at freeway speeds, this can hurt cooling

But i doubt it

You need to look at the possibility the condenser/rad is plugged, you can clean those ,,or the water pump is not up to flow needs
 

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Discussion Starter #18
Has the thermostat ever been changed? It's possible it could be slightly stuck closed.
No I haven't swapped out the thermostat. But the engine was swapped out for a new one at 175,000. I have about 245,000 on the car now. I would assume that a thermostat would have been part of the new engine but I guess it could have gone bad after about 75,000 miles.

I'll probably try changing it out just to see.

Is there a way to tell if a thermostat is bad by looking at it?
 

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Put the thermostat inside a saucepan of water together with a thermometer to monitor the temperature. Slowly bring the water up to the boil and note the temperature at which the thermostat opens. If it doesn't open at all, throw it into the trash and replace it.
 
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