My car has recently run into some problems. It started overheating which then resulted in the head gaskets getting replaced and the heads being redone. After that it continued to overheat. Now the radiator has been cleaned out, the thermostat replaced, the radiator hoses replaced, and all of the heat sensors have been replaced. It seems that the electric fan only kicks in when the air conditioning is on (other than that, it never comes on). I have no idea what else to do or what else could be wrong.

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1987 Camaro Sport Coupe
305ci 4bbl (LG4)
3.23 Gears
THM 700-R4 Automatic Transmission
All Stock

 

Check for the air dam... It's a piece of black plastic screwed into the bottom of the radiator to scoop up air.

About the fan not coming on... Two things come to mind. First, when you replaced the fan switch, did you use any kind of coating on the threads? The switch needs to ground to turn the fans on, so anything that's between the threads and the block could make the fans not come on.

Secondly, are you sure you replaced the sensor that controls the fan? There's two... One sensor on the top of the intake near the front that controls the temperature gauge, and another one on the passenders side of the block that controls the fan.

Other than that.... Is your water pump working? Check for a good deal of flow in the radiator.

Are any water passageways blocked?

I don't know what else to tell you.

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89 iroc-z 305 tbi
k&n filtercharger, open element air filter. nuffin' else

 

I also had the same problem of over heating. I discovered that the air dam was virtually non-exsistant. I picked up a replacement air dam at out local wrecking yard,($8.62 ) and that seemed to take care of the major over heating. But now I have a question. Does anyone know if there is an aftermarket air dam, made from a light weight metal, that I can buy to replace the very fragile plastic one? Thanks in advance for all of your help.

 

did you try replacing your fan switch? I recetly had to do that in my car. Try grounding the switch wire to the block, with a small piece of wire, if the fan turns on, its your switch. What i did untill I replaced the switch was run the a/c every time I was in traffic, that cooled it right down. Good luck with that switch, its a pain for big guys like me!! The air damn is also critical for cooling while the car is in motion.
Lockdoc, I don't think you'd want a metal air damn, its the first thing to hit the ground when your bottoming out. Its plastic so when it hits, it just flexes, and goes right back into place. If it were metal, well, I'm sure you can imagine. The sparks might be nice!

 

I did not replace the fan switch in my car. As for the air dam, mine is there and in decent shape. I'm guessing that's the only reason that my car cools off when I'm on the highway. The main problem is that the fan does not start when I'm driving, so when I'm in town the engine heats up and the temperature doesn't drop until I hit highway, but the fan still doesn't kick in on the highway. Both sensors have been replaced and we're pretty sure the water pump is working.

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1987 Camaro Sport Coupe
305ci 4bbl (LG4)
3.23 Gears
THM 700-R4 Automatic Transmission
All Stock

 

blue91rs, didn't see your post until after I just made that last post.
The fan did turn on when the we grounded the switch wire to the block. Can you please tell me where the fan switch is located and what is looks like??

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1987 Camaro Sport Coupe
305ci 4bbl (LG4)
3.23 Gears
THM 700-R4 Automatic Transmission
All Stock

 

The fan switch is located on the passenger side cylinder head near the back, between 6 and 8 cylinder exhaust ports. You can't miss it, it's the only other thing on the head that gets wires besides the plugs.

Don't confuse it with a knock sensor. The knock sensor is on the block and looks big and round, could be an inch in diameter.

If worst comes to worst and you can't find it, try and follow the lines from the fan to the switch.

Jason

 

I got to my fan swich from under the car, it was a pain. Its right were 89blwnrs described it. If you already found the wire, you should've found the switch. While you're dinkin around and getting dirty, you may want to do one more thing, while I was checking my cooling system, I noticed that the front of the radiator was stuffed with fuzz, leaves, etc. I cleaned it out GENTLY with a tooth brush, taking care not to damage the soft aluminum cooloing fins. I got a ton of crap out of there, and cleaned the rest out with a hose. it dramatically improved my cooling, and I would suggest you give it a try. JUST Don't bend any of the fins, airs got to get through there! Good luck!

 

I checked all of the fins on my radiator and they seem to be clean and they don't look bent. I also got to the fan switch unhooked it and noticed that the plastic on the connector was broken and I was thinking that I might be getting a bad connection. The connector still goes into the fan switch but it doesn't seem to fit in properly. Could this be the problem?

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1987 Camaro Sport Coupe
305ci 4bbl (LG4)
3.23 Gears
THM 700-R4 Automatic Transmission
All Stock

 

It turns out that my problem was that the computer was fried and because the computer controls the temperature at which the fan turns on it was causing the car to overheat. Thanks for the replies and help

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1987 Camaro Sport Coupe
305ci 4bbl (LG4)
3.23 Gears
THM 700-R4 Automatic Transmission
All Stock