after owning several thirdgens that always ran way too hot, im determined not to let this one do that for several purposes. my car is a 91 firebird 305 TBI with single fan setup. so far i have installed a 160* thermosat, aluminum water pump, heater core(in place of failed and leaky unit), and a 176*on/166*off fan switch that im having trouble getting to work(but thats another story). i also had the chemical flush done to the radiator to clean it out some and i also had the a/c charged so as not to add an extra strain on the cooling system. the 160* thermostat runs great and keeps the car cool when im cruising around, even though the fan doesnt come on. the problem is when i get into stop and go traffic in the extreme south carolina heat. the only way to get my fan to come on is to turn the a/c on. but even with the a/c temp set a bit warmer and the fan on low the engine temp still climbs from ~155-160ish to about 210+. i know this is a common problem to run into when going from cruising to traffic, but should it be to this extent? a 40*+ jump in temps seems like a bit much after 5-10min of driving in traffic. is the a/c causing that much of a strain on the cooling system? would getting an aluminum radiator or running a dual fan setup help lower the temps?

dont know if this means anything in comparison to my situation, but a friend of mine has a 97 T/A with dual fans and a 180* stock thermostat. he has a computer tune that keeps his fans on constantly, a/c or no a/c and no matter the temp of the engine and his temps dont move from 180. shouldnt my temps stay about the same even with the a/c on since the fan practically runs constantly?

thanks for any and all help you can give on the subject.

 

i got the 160* stat and my car runs on 210 all the time never had a problem and i live in florida lol.. with the a/c on it sometimes climbs to 220 lol....my buddy told me if your in traffic to throw on your defroster on your window to cool down the engine a lil it works belive it or not

 

I don't have the instuctions anymore, but I installed a Hayden Fan Control Switch that turns the fan on at 185, I found the instructions by searching the forums with the subject "Fan Control Switch". Good Luck!

 

ya my fans on a manual switch i turn it on when i want it on lol...usually right after i start it so i dont forget lol

 

well if you dont want to worry about the electrical fans and whether they are coming on when you want them to, go to a clutch driven flex fan. I run one because i was tired of the electrical fan nightmare and worrying if it was gonna come on or if it was running constantly which is no good either. If your electric fan runs constantly your gonna blow the motor on the fan, which has also happened to me and then your car will overheat. Flex fans are easy and will keep your engine cool all the time. Your thermostat should also be 180, 160 is too low, if your engine runs too cool its no good either.

 

Does the cooler (176) fan switch that you installed turn on the fan at all? If working properly, it should activate the fan without engaging the a/c. In traffic, or hot temps, the operational heat range shouldnt vary +40 deg. That's a pretty big variance, would lead me to suspect that the cooling system isnt performing as it should.

The later 4th gen computers can be flash reprogramed to activate the fans to come on at cooler specified temps. Did this with mine.

 

no it doesnt. thats the problem im trying to solve now. but even when it is fixed, i dont think it will make much of a difference right now as i drive with the a/c on all the time which keeps the fan on... ive also noticed that the temp will climb up if the car is just sitting in the driveway running, even with the a/c on. but the temp climb is much slower than when in traffic. could the problem be that the radiator isnt cooling the coolant enough and is faulty?

 

Send a PM to Reid Fleming. Ask him for a copy of the Cooling Fan Description and Diagrams (Service Manual). Might help you find the fault in the fan circuit. a/c in the summer is fine but, not in the winter

Sidebar question; are you loosing any coolant?

 

i have been checking it lately and there has been little to no coolant loss. i did notice a little bit coming out of the hose on the water pump today though. didnt get to tighten it cuz the motor was hot and didnt want to burn myself.

 

PM Reid Fleming for a copy of "Cooling Fan Description ans Diagrams (Service Manual). I'll try to send you a copy of it also. Hopefully, you can view the pics.

When you partially filled the radiator, did you check to see if coolant was moving? May sound silly but, have you replaced the radiator cap (old ones loose pressure)? Is your radiator brass or aluminum? I assume you have good coolant flow in both the upper and lower radiator hoses?

(With the motor running) Have you tried grounding the fan switch wire to see if the fan will activate? Or, checked the fan relay?

 

thanks for the pm. the link worked and i can see the pics

im not sure what you mean by coolant partially moving. i did change the radiator cap. the radiator is the stock brass piece. im assuming i do have good flow since the system was cleaned out and the hoses are brand new and the water pump i put on is a high flow unit.

the fan relay is not the issue. i changed it not too long ago thinking that was the problem but it didnt fix it... and i havent been real excited about going out to check the fan switch in the triple digit heat and 90% humidity we've been having this week

 

Was wondering if the coolant was being moved through your motor. From what you've said, it is, all is well, with the possible exeption of the fan switch to ground activation still being suspect. When this heat spell passes, you might try grounding the fan switch pigtail to see if the fan will run. If it doesnt, there a good possibility that there's an open in that circuit...

I empathize with your situation. I've tried trading with the devil to get my dual fans to work as they should in my IROC...long story short, installed two aftermarket fan relays and switches to independently activate them. No more hot motor or non-functioning fan circuits.

Regards

 

thanks, ill do that as soon as i can. if i ground the wire at the fan switch and it comes on, that means that the switch itself is bad and needs to be replaced right?

 

Yes. Simple to test. Disconnect the wire to the fan switch, run a jumper from it to good ground. Make sure your a/c is off. Start the motor and check to see if the fan is running. If so, bad switch. If not, open circuit in the fan switch relay wire.

Good luck! Let me know how it works out.

 

sorry to hijack, but where can i find the fan relay on a 92 RS? my old 88 donor had them mounted to the core support right in front of the battary. can't seem to find it there on my 92. thanks, Jim.

 

no prob. the fan relay is mounted on the firewall on the driver's side behind a plastic retainer. it is paired with another relay that powers the fuel pump. IIRC, the fan relay is the one on the left and the fuel pump relay will be the one on the right.

 

thanks for the reply. i was just poking around under the hood, and noticed that there was in fact 2 relays behind the ESC module. ill have to wire my toggle up tommorow, while i wait for the new fan switch.