i own a 1987 Camaro LT with a 305 since iv owned it the electric fan wont caome on when the motor is hot.. iv tried a few things like replaced the fan control switch which is located right hand side above the starter. i tried grouding the wire from the control to the body then truned the key on the fan will kick in it will also kick in when i trun on the ac or the defroster but not when the engine reaches high temp i repace the control switch thinking it was a faulty 1 but i dont think theres 3 faulty parts in a row..... if anyone has any idea what could be wrong pleace leave a message or e-mail me at gordonrocks@cogeco.ca thank you

 

What are you calling "hot"?

The factory setting for that switch is 235°; which is roughly at the bottom of the red zone on your gauge. IOW, in the factory's opinion (not that the factory would know anything about how cars are supposed to work, but just FWIW) the car does not need cooling until it reaches that point. Which is to say, it's COMPLETELY normal for it to do that.

How "hot" is it getting?

 

Replace your fan relay. It's a cheap part. Mine was located by my batter, a little before the radiator. My fan comes on at 220 and cools it down to 190.

 

The car is in the red zone

 

Sounds OK to me so far....

If the fan comes on when the AC is on, the relay is good. So it's not that.

Tape a thermometer, like one of those little cheeep ones you can get for AC work, to the upper rad hose. Let it sit there and idle until the fan DOES come on. See what the temp REALLY is.

Your gauge, which is NOT any kind of a "precision" "instrument", may just read higher than most. In which case, you can dink with fan switches FOREVER, and it won't change the gauge reading.

 

Yeah it could just be your gauge. I went through allot of trouble trying to figure out why my fan wouldn't turn on when it reached 240. Turned out my fan and relays were fine, and my temp gauge was off by about 30 degrees.

 

This is the very reason why I have accurate, precision AUTOMETER gauges mounted safely on my pillar.

Wouldn't go anywhere without 'em.

You can get one of those little temp guns that you point at something and it tells you the temperature. I think they are pretty accurate. Maybe that'll give ya an idea of the actual temp. You can check the temp of any device/area with one of those.

 

ok ill try that i did put a new temp censure in a mouth ago

 

Does the fan relay operate when you touch the fan switch wire to ground?

 

Check the cooling sensor.

 

yes it does
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Where is that located??

 

it is below the exhaust manifold on the passenger side of the motor. I replaced mine with a Hypertech cool fan switch. This makes the fan go on at about 175*.

 

Ive replaced that switch about 3 times now and it still want work

 

If the fan works when the wire is touched to ground, then the ENTIRE rest of the fan circuit is working.

The ONLY possible thing that can cause it to still not work, is the switch not doing its job.

Just changing the switch out repeatedly is no garantee that it's working. Keep in mind, the switch body MUST MAKE GOOD CONTACT with the head casting, in order for it to work. Too much Teflon tape, for example, coupled with not enough torque, or a buildup of old hardened sealer that needs to be cleaned out, will keep it from working. You can measure the resistance from the case of the sensor to the block or a bolt or the neg batt terminal or something, and see if you have this problem. Should be VER close to zero ohms. If it's any higher than a couple of tenths of an ohm, get a small toothbrush-shaped wire brush, and clean up the threads in the casting; and use the Loctite/Permatex "high-temp automotive pipe thread sealer with Teflon".

 

ok ill try that and ill tell you how it goes dose the hexagon part(the part you use the wrench on) have to touch the block because my switch will stop about 3/4 of the way in

 

The hex part doesn't really have to touch anything; the threaded brass part is all one piece with that.

 

It could be an inaccurate gauge, but it could very well be a bad temp. switch. In the 8 years I've owned my '86 T/A, I've had to replace the fan switch 5 or 6 times before the fan started working again.

 

Touch the fan wire to the out side of the temp switch, right at the switch. If the connection is good fan will run. Then try the brass. Then the block. This way is better than a meter because it will be the load (meters have very small loads).

 

You could got into the programming of your ECM and change the Fan setting's. So, no matter what the Sensor on the block or Relay are, as long as they work, your can control your Fan on and off Temps

 

A couple of years ago I had the same problem. I replaced the fan, Temp switch and the relay. But I still would get close too redline temp until I turned on the ac. I talked with my uncle (an Ex GM mechanic ) and the first thing he asked me was how is your timming? I told him it sounded ok, That the dealer Chilton book I had, had the first thing in the trouble-soultions for overheating was check the timming and then relays and such. With the engine sounding like it was ok, I could not believe it was that simple. So I replaced all the stuff and drove on. I drove for about an hour and it went into the red and blew the head gasket and started too somke, after replacing the gasket and heads and going through all that trouble and expense, I decide to spend about fifty bucks on a timming light and guess what! If I would have did what the book said, and my uncle, and bought the light. I would have saved about six hundred dollars and two days of my life. I have a 88 IROC-Z with a 305 TBI and my timming is 0 Degress before top dead center and I think yours is the same. Check the engine tag that is on the under side of your hood or on your radiator shroud for your specs. You will need to set it while in park and while its in gear and that should solve your problem.