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overheating? or just a faulty idiot light?

4K views 10 replies 6 participants last post by  FBN Firebird Nation 
#1 ·
I HAVE A 86 FIREBIRD V6. ive been having a problem with overhating, had a leak on my thermastat housing, so i replaced thermestat and put a new gasket on, now it dont leak. but the damn idiot light still glows, it will start out dim ad get brighter and then it will get dimmer again, i have to run my heat to keep the temp down. i did find out my alternators voltage regulator was fried out and the engine was getting too much voltage at high rpm, but i replaced the alternator with a new one and the light still comes on.

i also noticed my radiator fan doesnt turn on anymore, and i cant figure that one out at all.
but i guess my question or questions are...
anyone know what could be causing the engine to overheat?
how hard would it be to install mechanical gauges and is it even possible to install mechanic gauges?
and lastly.. anyone have any clues why my fan would randomly stop working?
 
#3 ·
Could be one of several things - or a combination thereof. Have you checked out the fan relay with a voltmeter? If it's bad, the fan won't run.

Does the light stay on at highway speeds? With air being forced through the radiator at speed, the fan is ineffectual anyway - it is only useful idling in traffic or at slow speeds. Have the radiator checked for leaks and fluid flow. Because the coolant system is pressurized (you were on the right track with the thermostat), any leak will prove detrimental.

On 4th Gens, the temperature sensor for the fans is separate from the sensor for the gaughe/idiot light. Don't know about 3rd Gens, but make sure all temp sensors are okay or replace them.

Hope this is helpful.
 
#6 ·
yea the light stays on when im at highway speeds. the radiator doesnt leak and it sould flow fine, the coolant i drained to do the thermastat was clean and when looking into the radiator from the cap it looks clean. my radiator cap has bee a lil hard to get on and off so i just got a new one just now. i also grabbed a new temperature sending unit as well. i didnt check the fan relays voltage but i grabbed a new fan relay switch anyway, just waiting for the enging to cool down so i can work on it. ill let you know how it turns out later on. Thanks for your help, hopefully i can clear this problem up.
 
#5 ·
http://www.evanscooling.com/main21.htm

The link above contains some good science and theory behind the realities of cooling systems. HPP ran an article about using the Evans NPG Non-Aqueous (no water) cooling products in a Pontiac engine in a '67 GTO a few issues ago.
 
#7 ·
ok so i replaced the temperature sending unit, radiator fan switch and it runs cool now, the light will barely come on but i can deal wit that. as far as the fan, i disconnected the relay and took a wire and jumped the 2 wires for the fan and the fan turned on, so the fan motor is good, so i ordered a new fan relay. thanks everyone for your help, def aid'd it the savior of my tiny v6, lol.
 
#9 ·
Are you sure the new thermostat is good? Just because it's new doesn't mean it's working properly. Good luck.
 
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