JP86vette

Have had this 1986 coupe since May, it has always run 200 or less temperature. Lately it has been going to the 240 range, which in reading this forum seems to be no reason for concern. Today I started it in the driveway to see when the fans would kick on. The temp reached 239 and the fan closest to the front end kicked on. The temp went down to 230 and shut off. The question I have is when is the fan closest to the engine suppose to kick in, it never runs. Any help would be appreciated. Thanks.

Cliff Harris

That fan is controlled by the ECM. The ECM uses the CTS (Coolant Temperature Sensor) on the front of the intake manifold to determine the coolant temperature. The ECM is set up to turn on the fan at 228°.

WVZR-1

Does the fan run when the AC is turned on? There's a fuse (3A maybe) in the IP fuse box likely labeled C FAN. With the KEY ON (engine off) jumper A & B in the ALDL and fan should run I believe. Does it?

If NOT, I'd say the first check might be to see if the fan runs with 12V direct to fan and if it does you check/confirm wiring at the primary fan relay.

Do you have any RUN issues?

Do you have maybe the FSM for the car?

JP86vette

The fan does not run when the AC is turned on. The fuse is good. It did not run when I jumpered A & B. Looks like the next step will be to see if the fan motor is any good. I won't be able to get that checked for a couple days.
The car runs fine, was out on the highway today, temp stayed around 192 while driving.
Thank you for the help.

JP86vette

Any pic of where that might be? or what I should look for?

wzschirnt

The fan that kicked on at 239 is the SECOND fan that should come on. The first one comes on around 225-228. That one (the 228 fan) has a problem. It also should come on when a/c comes on at any temp, I believe.

Good luck.
walt z.

Mr.Grandpa2U

My '96 had a similar problem. I added refrigerant to the A.C. system and for whatever reason, that fixed the problem. Now both fans will come on when needed.

antfarmer2

Is your compressor comming on for the ac? If not add freon and good to clean your radiator.

vader86

This sounds like a fan motor or circuit problem, the main fan should be coming on at 228F and is ECM controlled.

The auxiliary fan, if your car came with it, is in front of the radiator and should come on about 10 degrees higher, it comes on via a temperature switch in the head.

While you are in there I would suggest at least cleaning the space between radiator and condenser unit.

JP86vette

I ordered the fan relay after checking to see if the fan itself was ok, which it was, so I installed the relay today and the fan came on around 180. seems a bit low, but that is how it worked before it went out.
Thank you all for the help, I appreciate it.

Tex Pete

Hi there I have a 1984 corvette with crossfire injection. The 2nd day i purchased the vehicle the engine overheated well above 260 degree Fahrenheit. I opened the hood and as soon as the hood open the coolant back charged into the reservoir causing me to receive 2nd and 3rd degree burns on my right hand and a lovely visit to the emergency room with weekly visit to the county burn center for treatment recovery. So after being discharged from the hospital to play it safe and make my girlfriend content i had the corvette towed to a Chevrolet dealership where they discovered that the cooling fan relay was faulty and the electric cooling fan had shorted out as well. The dealer also wanted to replace the radiator but i took the car to a trusted mechanic friend of mine and had him flush the heck out of the cooling system while he flushed the cooling system he removed the 220 degree Fahrenheit thermostat with a 160 degree Fahrenheit thermostat. Since doing all this i never have had one time an overheating issue. that includes sitting in the worst bumper to bumper traffic on the hottest summer days city life can offer. I also plan to upgrade the computer chip that will also command the electric fan to start up at a lower temperature among other performance enhancements. for roughly an extra 110.00 you cant go wrong. Hope all this information helps you out.

A Peter C4

Never heard of 220 degree stat or is that centigrade degrees?

Tex Pete

Also by the battery there are 4 fusable links one of which is the power source to the fan. My fusable link wiring wore out over time and i had to buy a new in line fuse kit. Now the fuse is replaceable. Secondly to repair that potential bad spot you have to remove the battery and obviously run your wiring off the Auxilliary line coming off your battery terminal. There are four more fusable links all by the starter where the battery terminal line comes in to power the starter but im almost certain those would have nothing to do with the fan.