intermittently running hot

[JAXXX]

I have a 95 gt with ford explorer lower and cobra upper intakes,

My problem is this the car will run hot alot of the time going to L on normal when it usuly rides strait up and down. i do not always hear the high speed fan kick on and sometimes it WILL kick on while running warmer and cool down.
What i am wondering is should i replace the fan controll switch mounted to the fan its only 35 bucks? and it its not that what else could it be? kind of acts like a short in the wire because it intermittently fixes itself.

 

[BlownFiveLiter]

To replace the fan control, you'd have to replace the CCRM, and that can get quite expensive. It's been said before that you can't rely on the factory gauges for an accurate depiction of what's really going on with your engine, so adding an aftermarket temp gauge would definitely help. If you're concerned about your fan turning on, apply 12v to pin 14 on the CCRM to test the low speed function, and ground pin 17 to test the high speed function.

 

[HISSIN50]

I agree. You need it to act up (low speed to not be on at 208*+ or high to not be on with Max AC) and then do your testing. See if CCRM Pin 14 has 12 volts for 208*F+ temps or if Pin 17 shows continuity to ground with Mac AC on. Diagnose from there.

Also consider that your ECT is out of calibration.

Good luck.

 

[Dino Dino Bambino]

The L of NORMAL should equal about 222*F and that's not high enough for the high speed fan to kick in.
I had thought until now that the high speed fan in my Stang wasn't working at all (only the low speed works when MAX AC is on). I just found out a couple of days ago that it does work after all, but only when the gauge has gone well past L and is almost in the red zone. How did I find out? I installed a new OEM 192* t'stat only to find out that it was sticking closed causing the gauge to peg into the red. Needless to say I was pretty p***ed off about that. I took it out again and left the engine without a t'stat for now.
The high speed fan works when I ground the wire from pin 17 of the CCRM, so I'm going to link that wire to a ground via a toggle switch so I can have manual control of the high speed fan. The more expensive alternative is a DC control for the fan operation.

http://www.dccontrol.com/

 

[BlownFiveLiter]

If I'm not mistaken, you'll need a relay to run the ground through a switch. You may end up burning the car if you don't, since it's still high amperage running through the ground.

 

[HISSIN50]

Matt, the ground input (CCRM Pin 17) is on the control side of the HEDF relay. No relay needed.

 

[BlownFiveLiter]

Ah, good call then. I don't have a wiring diagram, so I was assuming that was the case. I stand corrected

 

[TGgnatsum49]

Before i bought my coupe i had a convertible and i was having the same overheating symptoms. I first replaced the thermastat w/ a new oem one and the problem continued. A month or so later my heater core went out completely and started leaking on my feet while driving... it sucked. i then replaced the heater core, might i add is a complete pain in the arse. After that the thermastat sat consistantly beween R and M.

 

[Al J]

Re the last post:
I don't get it.
How can the heater core effect overheating adversely?
One long-time band-aid for overheating is to put your heater ON.

 

[Chythar]

Wow, talk about raising the dead!

If your heater core is blocked, it will keep the coolant from circulating right and it won't cool down.