hello. I have a 86 trans am, 305 TPI, with electric fans. I recently drove my car off the road into a lot of snow. Ever since then i have been overheating. At first i just thought it was my fan, b/c i didn't see it turn on. So i check the fan, wires, and replaced the relay, along with the coolant temp sensor, and fan switch. I have also checked all hoses and even changed the radiator, with a new thermo of course. My car will overheat at idle. I flushed the system, but i still don't know what is going on. The air dam is not the issue here. Its fine. I'm kinda thinking that the fan isn't even the issue here. Becuase in the past the car would never get above 200 and the fan never went on. And even when my temp gauge reads 250-260, my fan still doesn't turn on. Please help me. I am so lossed and i can't figure it out. thanks.

 

You said your car went off road and you replaced just about everything in the cooling system. Have you checked to make sure there is no restriction to air flow under the car to the rad.?
Also you should run a search here and get those fans running. Does yours have the duals? You also said that "the fan never went on before." Please clarify this. If you have dual, neither of them went on, or just the secondary never came on. If you have a single fan, it never went on!?! Let me know.

 

Thanks for responding, i really appreciate it. Well my car has a single fan. This fan then goes to a relay that goes to the ecm, ground, fuse all time, and for a fuse for ignition. I have already changed the relay, coolant temp sensor, fan switch (which i is located on the back of the passenger head). Today i checked for restrictions to the rad. but found nothing. I am thinking that maybe something is messed up internally. But i'm not sure, please respond. Thanks a lot.
Christopher Pawson
pawson@udel.edu

 

did you make sure you got all the air out of the system, and also what kinda coolant mixture are you running..

so when does the fan come on when your car is just idling?

with no airflow the car will start to run hot so the fan should come on alittle after 220 on the guage...


how does the car run on the highway?

 

I have a single electric fan!
Ok first off, theres a 50 50 mixture. And yes, the fan never comes on.
I read if you bridge your computer so you can read the codes, all your sensors are activated and the fan is supposed to come on as well. Well my fan never comes on.
I checked all the wires to the relay with the computer bridged, and every line seems fine, yet no fan motion. Another thing is today i pulled the thermostat out, so theres no thermostat in the car. But it still overheats!!! So I'm starting to think that the fan isn't even the issue here.
The car overheats either at idle or in motion on the highway.
Today someone told me that there might be a problem with my EGR valve, could this be???? Someone also told me that i may have cracked a head gasket, but I see no leaks or compression loss. Can yah help? Thanks again.

And the weirdest thing is the car never even pushed 200, until i drove off the road and got it stuck in snow!!! This is when the problem occured.

 

Yes without a stat your car will overheat and without a fan running your car will overheat. I have never encountered a faulty EGR valve causing and overheating condition, I don't see how this could be. I have no EGR and have no cooling issues. GET YOUR FAN RUNNING. Try to simiply jump battery voltage to the fan and see if it begins to run. If it does then you know it is able to run. Fan motors go bad too. I would put in an OEM temp stat or close to. Stay away from the low degree stats, it won't do you any good. If your car will sit at idle and overheat and the fan never comes on, you have a problem. BTW about what temp. is it reaching? Good luck.

 

Thanks again for your help. Well i wired my fan to a switch straight off the batt. so i have full control of the fan now. Although the temp is still climbing. With the fan on all the time, i run about 200 degrees. But the car is still heating up.
This is just a temporary solution, until i can find the real problem. Because that fan is basically on when the cars on to keep it from overheating, and i don't want to burn out the motor.
Does anyone have any other ideas as to what this may be?
Thanks again.

 

I thought that the single fans were controlled by a fan switch in the pass head? , my 89 is

 

Ok, so i finally just wired the fan to a switch, which i can toggle whenever the temp starts rising. Why wouldn't my fan go on in the first place, could my ecm be bad?
And why do you think the car is overheating?
Do you think i could have a cracked head, (what are the signs of a cracked head).
Also no one thinks it could be the polution controls???
Thanks again.

 

i have somewhat the same problem as you. Instead of wiring the fan directly to a switch(plan on doing that when it gets warmer) just turn your AC on, once the AC turns on the fan should instanly be activated. I've never done it myself but logically thinking your car is going to over heat without a thermostat, coolant is constantly be pumped threw the motor and has no time to cool down, or atleast thats the way i look at it.

As for a cracked head check your oil, it may be over full, watery, or have a white substance in it, as far as i know anyways.

 

Since you went 'offr-roading', you may have torn off the air deflector from below the radiator. Without that you won't get any airflow at highway speeds. Also check maybe with an air hose to see if air will flow thru the radiator. Check between the radiator and the a/c condensor for any leaves or crap that may have worked it's way in there. Be sure to put the stat back in, without it coolant won't stay in the radiator long enough to cool off.

 

He said the air deflector was intact or more correctly he said the "air dam" was still in place. I hope he is talking about the same thing.

I had a Chevy parts guy order me the wrong part once. I said air deflector, he ordered something else that he called an air dam. Not even remotely the same piece. I have almost entirely taken apart my car since buying it 4 years ago and I have not come across the part he showed me on my car.

 

hi thanks for all your responces. Well the air dam isn't playing any roll here, because it is overheating at idle. Now i'm going to put a new thermostat in since you guys said that it won't cool down without it. But I kinda still think there is something else wrong, maybe a cracked head gasket, becuase i have been seeing a significant amount of condensation coming out my tailpipes. The weird thing is i can't smell any antifreeze, oh well, what do you think i should do from here. ??? thanks again.

 

Had my fan checked at the garage, and it comes on at 229 and off at 219. The fan also does not turn on when you turn on the A/C. It only turns on for two reasons. The engine is too hot, or the pressure in the A/C is too high. So keep looking. On my 86 TRANS-AM, I added a second manually controlled fan to help out when needed. I used the fog light switch which I moved over under the temp gage (I wired it so the "on" light was activated when I was running the fan). I still feel I don't have enough air flow. I lubed up the fan, but I am going to get a new one with lots of CFM.

 

The Spal dual 11" fans move some air!!

 

thanks everyone for your help, but my car is still overheating at idle. I figure screw it becuase its an overheating mystery, so this summer i'm just ganna drop a 400 in that mo fo, and leave it appearing stock. So i'd watch out chevy fans.