I start the car: 1982 GS. About 3 seconds later the stock mechanical fan kicks on, and stays on. I can turn the car off, let it cool down for a few hours, but as soon as the engine turns over, the fan is on! I have to let the car sit for at least 48 hours before I can start it without the fan coming on, and then its the same thing! 3 seconds, and the fan is back on for the day!
Now, the logical thing to think would be that the car is overheating. I just pulled the rad, had it flushed, painted, pressure tested and welded back to the mounting brackets. I replaced the 3 hoses and 6 hose clamps connected to it. I added almost 2 gallons of 50/50 antifreeze-water premix, worked the air bubbles out, added a little more. Started the car, 3 seconds later, fan comes on, stays on.
Any ideas?

 

whelp, youre way off. there isnt anything wrong with your cooling system except for your fan. youre fan clutch is stuck in warp speed.

a buddie of mines 83 did this. the fan was constantly on. whenever you opened the hood you were greated with rushing air. the car stayed on the really coolside, which isnt too good. it doesnt allow for the engine to get to correct operating temps.

let your car run for a few minutes. while doing this watch your temp gauge. if it stays near the bottom(which in 99% sure itll do), then all you need to do is instal a new clutch fan tahn you can get off the forum for dirt cheap. i have one i would give you for free, but since youre so far away id send it to you for the price of shipping. im not 100% sure it works, but im 80%

 

If you are 100% this is the problem, then I am willing to take an 80% chance fixing it.
And yes, the temp needle stays buried. Would it be possible that the temp sensor is wacky and just telling the fan clutch to stay engaged?

 

no, the fan is mechanical. there arent any wires running to it. i could be wrong, but my guess is that its the fan clutch. dont drive your car hard, or at all, when the temps are that low.

to check to see start the car and if the fan starts right after the car is started, same as my friends did, its the fan clutch. leave the car running and open the hood and the fan will just shoot air out of the hood nomatter how long you leave the hood open.

 

shut off the car, give the fan a spin by hand, if it does 2 -3 rounds then it is just fine. Leave it alone.

 

The first time I start the car, there is about a 3 second delay from when the car reaches idle to when the fan kicks on. Every time after that, the fan is on with the engine. Something is telling the clutch to engage the fan! There has to be, if the fan has the option to be off, something electrical is working the clutch. I would just like to figure out what that is/how that works, verify that it is working, and then I will replace the fan. Maybe even go electric (but I would like to avoid that to much $$ IMO).

 

I will try this ASAP after work. If it spins freely, what should I look at next?

 

It wont Spin Freely.

Freely is 6 - 10 rounds and means it is bad, As long as it goes around a few times then everything is golden and you should leave it alone.

the fan is mechanical, And there is a clutch in there that enguages to make it spin faster as the fan gets hot. I had an 82 that acted this same way car ran a 1/3 guage, was real tempted to remove it an use it on my car that runs a little hot.

 

+1 for a working fan clutch...I had the same issue with my '85. I found a fan clutch at the local salvage yard, major difference. You might also try just cleaning yours, when I removed mine it was so corroded with crusty grossness that it couldnt possibly work.
Or go with an e fan;-)

 

OK
Today after work I will make sure the fan spins 2-3 times with my hand. If it does not, I will take it apart and clean it up. There aren’t going to be any nasty springs and things inside it, will there?

 

It's not an electric fan, so it WILL spin any time the engine is running.

 

So why the 3-4 second delay with the first start of the day? I don't think it should be on constantly, won't that make the engine to cool?

 

On the first start of the day, it will spin up and then slow down to a fairly slow speed and stay that way until the engine heats up. While cold and running, you should be able to stop the fan with your fingers. This is dangerous and I don't recommend it. Anyway, you can stop the fan from spinning altogether. Then when you let it go, it will eventually catch back up to the engine's speed. A hot fan will offer much more resistance and not even I would attempt to catch it.

If the engine stits there and overheats, you should look at the thermostat. That's what I'm fighting right now. It's the second one in a row to do this. I went from a crappy stant, top a stock FC thermostat that seemed to have an awefully stiff spring. I have yest to try an FB thermostat which looks and feels correct. I hope third time's the charm.

 

Quick way to check it. With engine off, turn the fan. If it turns very easily, it may be going south. If turning the fan also turns the engine, it's junk. You should be able to turn it somewhat easily, but not totally freespin it.
There should be a little resistance while turning it if the engine and radiator are cool. A little more resistance when they are warm. The fan clutch has a viscous fluid in it, that increases the drag as the fluid gets warm.
If your fan is spinning at the same speed as your engine all the time, you will hear a loud roar from the fan starting around 3-4K, and it will kill the performance and fuel mileage.

 

The fan has a bi-metal themal strip that engages/disengages the clutch, depending on the temp of the air passing over it. When they fail, it is usually in the full lock up mode. Even if the clutch is not locking up it will spin some some. At speed on the highway, it needs to be able to spin, freewheel, from the air passing through the radiator. If it didn't do this, the engine could overheat on hot days by the fan restricting air flow through the radiator. Same thing can happen if the clutch is locked up.

With the engine running, take a broom and use the bristles to slow/stop the fan. If it doesn't, replace the fan, no biggie.

 

He says the car is not running hot at all.

 

Well in that case, I'll let this audio clip explain what a healthy fan should sound like. Just download, unzip and play.

 

^^^

That sounded like a jet starting up!