Im new to the forum and the vette world so please bare with me while im in the learning process. I have recently bought a 85 with 85k miles and I am currently in the restoring process and starting with the Mechanical first. I have noticed that the Temp is running around 230-240+ so I was very concerned and then noticed the Fan doesnt seem to be kicking on. Can someone please assist me with a starting point to this problem and also what a normal operating temp should be for a vette of this yr. All responses are appreciated. Thanks!

 

I've had the same problems with my 1990. Turns out the usable link burned out. Check that. It's behind the battery, with a bunch of orange wires running to one post. See if any are broken, where they burned out. If that's not it check to see if the relays (left; mounted to the radiator shroud) are OK. Try jumping them to make sure they are grounded and working. If thats not it, check the sensor that kicks the fan on (underneath the plastic inake hose; either by or on the water pump.) It's a 2 wire connector. Jump that and see if the fans kick on.

Good luck!

 

I'm a LT1 guy, but I wanted to welcome you to the FORUM. I like the handle you came up with. We're all Corvette Freaks here. You'll get a lot of very useful information here. When you figure it out, show us some pictures.

As far as the fan problem, I'd hot wire the fan just to make sure it is working. Then trace back to make sure the wiring is okay. Next, hit your service manual. :cheers:

 

:seeya Welcome to the forum
Your running temps should be lower. Main fan should kick in about 228' and aux fan(if you got 1) around 238. Apply a jumper wire from terminal "A" to terminal "B" on the ALDL connecter(underside of dash above right knee) and turn ign to on. This should start the main fan. If it dosen't run locate fan relay(on inside of inner fender near battery). Turn key on and apply ground to terminal "B" on the relay. If the fan runs there is a problem with ecm circuit. If it doesn't check for power and ground at fan. If none remove relay and check for 12 volts at terminal "D". If no voltage check fusible link near battery. If there is voltage check for 12 volts at terminal "C". If none there check fuse in panel. If all power is at relay connector jump terminal "A" to "D". If fan runs relay is bad.
:cheers:

 

Thanks for all the quick responses I will be sure to go through them all and Im sure one of these will surely fix the problem. Thanks again for all the help. I hope I am able to return the favor some day. Have a GREAT new years.

 

That was a great job 86'. A wealth of information :iagree:

 

:iagree:

 

:iagree:

 

:iagree: RIGHT ON. :thumbs:

WELCOME! :cheers:
I just went through this with my 86 this week. A paper clip bent into a "U" shape works well to ground the "A" "B" terminals under the dash (the two upper right hand terminals). I inserted the paper clip and switched the ignition to the "ON" position. Fan did NOT come on. With the paper clip inplace and the key in the "ON" position, I located the fan relay. I disconnected the connector and jumped the "A" and "D" terminals together (the far left and the far right terminals" The fan DID turn on. I replaced the fan relay for $10 at a local parts store and all is well now. Took me 10 minutes total. :thumbs:

Other suggestions to keep that heat in check.

1. Conisder a low temp fan switch. It will turn your fan(s) on at 200 degress and off at 185 degress instead of the 230ish factory range. EASY to install and inexpensive too. I got mine here http://www.madvet.com/shop?frame=3.138.944 If your state requires Bi annual Smog Inspections keep your stock switch on hand. They will not be able to get the car to reach temps much over 200 degrees for testing. It will keep that heat in check in traffic.

2. Consider replacing your stock 195 degree thermostat with a lower temp one. I went with a 170 degree thermostat from TPIS. It will lower coolant temps. These are readily available and range form 160 degrees up.

3. Consider drilling 4 small holes in your thermostat, per TPIS recommendation. (which ever one your may go with, factory or aftermarket.) I did this to mine and my temps IMMEDIATLY dropped from an average of 210- 230 to 175-200 with just this mod alone. The holes provide a continuous flow of coolant that will eliminate those high temp spikes. (Why the GENERAL did not think of or do this beats me.:confused:)

4. Ensure that the rest of the cooling system is in working order. Check hoses and wash off any debri from the front of the radiator and check the coolant level.

Do this and you WILL keep that heat in check.
My 86 seldom sees 200 degree plus temps.:D :D

Oh and last but not least. since you just got that Vette and new to the "Vette world" use that paper clip and this web site to clear any codes that your Vette might have had from the previous owner.
http://www.c4vettes.com/ecm.htm
It will guide you throught the simple process. It has proved INVALUABLE to me and I have cleared ALL the trouble codes in my 86 myself. She stays cool and perfoms like a son of a gun when I get agressive with her.

Good luck man
:D :thumbs:


[Modified by 86PACER, 1:30 AM 12/31/2003]

 

Ain't this a great forum? There is more info available here than in the best service manuals :thumbs:

 

Welcome to the Forum..

The tips given on this thread have been excellant.

Probably the first thing to check if your fan is not coming on is the fan fuse.
The fuse panel is accessible with the passenger door open; it is on the right end of the dash. Check the three amp. fuse labeled "C. FAN", it is on the right side of the panel in the second row.
If the fuse is blown, there is a short in the system; possibly a shorted (defective) fan motor.

Lots of luck and give us an update if possible.

Mark

 

Thanks again everyone. I have tried putting a jumper between terminal A & B and the fan came on. Could someone please let me know what that means and what I should do next. Again I sure appreciate all the help. This forum ROCKS.

 

Your coolant sensor (under throttle body) may have the wiring pulled off or broken.
Sensor may be bad also.
Are there any codes stored. 14 or 15 maybe
Check this link for reading codes
http://www.c4vettes.com/ecm.htm
:cheers:


[Modified by AGENT 86, 8:25 AM 12/31/2003]

 

I am replacing the sensor now. Is the fan suppose to come on as soon as the key is turned or does it wait until the vehicle warms up etc. This is my first corvette so im not sure what normal is when it comes to the fan running. Thanks

 

The fan is thermostatically controlled. It may never come on if don't reach the activating temperature or you always drive over 35 miles per hour.

 

Just one hour ago, we just finally figured out my father-in-laws 84 over heating problem. First it overheated and blew coolant everywhere, then the fan ran as soon as the key was turned. After jumping terminals, unplugging everything and testing everything, we gave up. We decided that a wire must be grounded somewhere from the temp sensor. I traced the orange wire from the sensor and found bare wires near the starter. I cut out the bare section and re-routed the wires back to the sensor and presto.....it works! Not to hijack the thread, but we have been working on this problem for a few weeks with no luck, so we had high-fives and beers to celebrate...... Good luck with your overheating.... :thumbs:

 

Here's another thing for you to look at in addition to getting your fans running. If you are cruising in outside temps like we have currently you shouldn't need your fans running unless you're in stop and go traffic. If your temps are high even when you're up to speed I'd recommend cleaning out the crud between your radiator and air conditioning condensor. These cars suck up leaves and garbage like they're street sweepers and it all gets deposited where you can't see. Take the fan shroud off and you'll be very surprised if it's never been done.

Here's a link to a tech tip that explains the process. https://www.corvetteforum.com/techti...D=53&TopicID=2

Ron

 

It means that your fan works.

Do this next

1. Ground the "A" and "B" terminals again and insert the key, leaving the ignition "OFF"

2. Locate the fan relay (little black box right below the brake master cylinder.)

3. Unplug the electrical connector at the fan relay.

4. Turn the key to the "ON" position.

5. Connect a wire from the far left terminal to the far right terminal on the relay connector.

If the fan DOES come on again, you now know that the fan and the fan relay are both good.

 

Thanks again everyone for the great advise. I have tested to the point that I know my fan and relay is working but for some reason the fan still wasnt coming on so I kept on searching and I have found a wire down by the starter ( GREEN WIRE ) which is broke off and Im not sure exactly where it goes but the car starts great. So for the time being I have took the A Terminal (BIG BLACK WIRE ) off of the fan relay and ran a wire from the A Terminal to the Hazards Fuse in the Fuse box. I dont like the fan running all the time when I start the car but atleast im not overheating any more. I figured this would cause less damage than overheating. If anyone knows what that green wire might go to I would sure appreciate the help. You guys have been great. Thanx again.

 

Could be for the knock sensor :confused:
You can splice a wire into terminal "B" of relay and run the wire to a switch in the cockpit. The other side of the switch goes to ground. This way you have full manual control of fan till you find the problem. You would probably choose to keep switch even after you fix the problem.
:cheers: