96 GT running hot

[TIGGER]

I bought another GT coupe last year as a beater to drive around. The wife took liking to it since it a 5 spd so she has driven it more than I have since I got it. The water pump started leaking around the 4th of July. I changed it a couple weeks ago. While I was there, I changed the thermostat and flushed the whole cooling system and put fresh coolant in. This past weekend, I did a bunch of suspension work to it. Yesterday I took it to get aligned. Temp was around 94 outside. I ran errands after the alignment with the AC on. Temp slowly crept up to the A of normal. It took a bit to get to the A. For a while it hovered around the M. I turn the AC off when it hit the A and drove with the windows down. Temp went down to the M but did not drop lower. This was the first time I really drove it since the water pump. In fact, it has been a while since I have gone more than a few feet in it. Wife says temp is always in the middle but she noticed it going up at a light last week but then as she starting moving it went back down. Not sure if it was like this before the changes or not.

Temp is about the same today. I drove our 96 Gt Vert and the temp gauge did not go past the middle of the R. I was dead in the middle of the R the whole time. I also changed the thermostat on the vert and did a flush a few days after the coupe so it has the same napa 195 deg thermostat in it.

While I do not think the coupe is "overheating", I think it is running hotter than it should. Any ideas on what to check? I though about changing the thermostat again but I do not know if that is what is really wrong. Wife wants her car back but I am hesitant to let her go bombing around in it if it is going to eventually overheat. She may not notice when and if it does

 

[RaggedGT]

I’m sure you did all the coolant burping/top off etc. Is your cooling fan kicking up to high speed when the temp gets warmish? Fan running with the ac on?

 

[TIGGER]

Yes I burped it. Car has over 300 miles on it since I did the pump, flush, and thermostat. Fan is on with the AC. Not sure if it is on high or not. Is there a way to check it?

 

[HemiRick]

my 91 has this same issue, runs hot, but doesn't actually overheat....I replaced the sending unit no help.

 

[TIGGER]

It is currently low 80's out, I just took the car for a drive. Temp never went above the R. AC was on and the coolant fan only was on low. Does anyone know how you test the high speed function?

 

[RaggedGT]

It’s been a minute since I’ve really looked into the multi speeds on stock cooling fans-I believe if you unplug the temp sensor for the fan-it’ll lock it into high speed while it’s unplugged. There also should be a maxi fuse in the under hood fuse box. If those things check out, you can check for power from the ccrm to the high speed wire at the fan-should be a 3 wire plug

 

[TIGGER]

Any idea where the temp sensor is for the fan? Does the ECU need to trigger the need for high speed fan for the CCRM to have power at the wire? Or does unplugging the temp sensor do that for you?

Appreciate your help

 

[RaggedGT]

Im pretty sure it’s the sensor I marked on this pic-

The sensor triggers the ccrm,but unplugged it “Should” default to high speed. Fingers crossed I’m actually helping ya lol

 

[TIGGER]

I Just went out and tried both GT's and neither kick the fan on when I unplug that sensor.

 

[manicmechanic007]

Damn straight they run hot. Scary if you are looking at the gauge. The ones that have a CCRM simply run 9 volts to the fan for low speed then switch to 12 volts for high speed. Just check the voltage to check the high speed function. Some early ones like your 96 has a ballast resistor in conjunction with a stand alone fan relay attached to the fan shroud and had no CCRM. They test the same way. The ect drops to roughly .4v when it gets above about 218 degrees F and the processor requests fan function (turns on the fan). I have watched hundreds of these with a breakout box on the ECT wires waiting for the fan to come on while monitoring the voltage with a DVOM

I Just went out and tried both GT's and neither kick the fan on when I unplug that sensor.

Unplugging the sensor does not turn on the fan. The old ones do not go into limp mode. The check engine lamp just gets illuminated and it will overheat for sure

 

[manicmechanic007]

Overheating issues for years as far as the gauge is concerned. They get damn hot before the ECT drops to .4v The 2.3 was the worst for damn near boiling over before the fan ever kicked on. Replaced a whole lot of ECT sensors and cooling fan switches. The CCRM's melt wiring and connectors on a regular basis. Interrogate the cooling fan itself by smacking it around some

 

[TIGGER]

Couple questions. I thought all 96's have the CCRM? How can I tell without ripping out the inner fender liner? How do I check for the high speed voltage? Does the engine need to be blazing hot and about to overheat? I assume I can check the low speed by turning on the ac. I assume both are not hot at all times when the engine is running or are they?

 

[RaggedGT]

In the past-for me-unplugging the sensor while the fan was running netted me some high speed action-but I mighta just got lucky-as mentioned above-ccrm’s tend to be the culprit- you can goto the pins on the ccrm if checking the connector at the fan or beating on the fan does not answer much-

That ccrm pin out may not be the correct one for your car-it was a quick google-fu search