MikeinBloomfield

Twice over the hot, Jersey summer, my car overheated in heavy traffic. While the red light on the temp gauge never came on, the needle climbed to the top and the system warning light came on. Luckily, I was at the end of the trip both times when this happened, so I was able to shut the car off overnight.

The car's temperature is perfect at highway speeds, right between the two lines. But in stop and go, the temp needle starts to climb. Turning on the AC seems to make the problem worse. Driving on local roads, the needle sits just north of the middle.

I have read lots of threads here, and the general advice seems to be if overheating is "speed-related," its an airflow problem, not a liquid flow problem.

So I attempted to refill the fan clutch with silicone fluid. After taking off the fan clutch assembly, I was dismayed to find that the fan clutch was stamped "2008," which I assume means this was changed four years ago by the PO, probably trying to fix the same problem. Anyway, I proceeded anyway and the fan clutch took about a bottle and a half of fluid, but this has not solved the problem.

So what's my next step? I have to assume that the fan clutch still isn't working. You are supposed to be able to hear the fan increase its air flow at 2000 RPM, I'm going to check that this weekend.

Used fans are (relatively) cheap on Ebay, should I take a chance on one? I've read a thread here where that solved the issue, but I keep going back to that
"2008" stamp. Could it be that one that new is also bad?

Is there a way to check whether the radiator is blocked?

FLYVMO

A radiator shop might be able to clean it, but I am not sure they can get 30 years of deposits out (if original radiator). I had a similar problem on my 86.5 and first removed the mechanical fan, and replaced it with a dual Spal setup. It helped somewhat, but still ran hotter than usual in traffic. Finally installed a thicker core, all-aluminum radiator and the car ran much much cooler. This was after I had replaced the thermostat and water pump.

Temperatures were very stable and never fluctuated significantly, even in 98 degree Florida summers. The stock radiator has enough cooling capacity so a factory Behr will work fine. I think 928Intl. and 928's-r-Us have them in stock.

Cheers!
Carl
90GT Project

Ethre

Was this what you tried before?
http://www.nichols.nu/tip482.htm

Probably worth taking an air hose to (gently) dust out the radiator. Block off the air intake (so you don't blow dust into the engine) and use an air wand. If you put it to close to the radiator you will bend the fins (or use too high of a pressure) but from the inside you should be able to gently blow out some of the dirt.

If you turn on the AC you are effectively moving heat from the interior of the car to the engine bay.


Edit: You can also try pulling the radiator and washing out the fins. Regular water will get rid of the some of the dirt pretty well but make certain that you get it as clean as you can. Otherwise you can end up with some dirt being more compacted than it was before.

G8RB8

Use the lowest ratio of antifreeze you can to avoid freezing. Use water wetter. +1 on both the above suggestions, plus you can add a pusher fan in front of the A/C condenser. If it heats up in traffic and you have to keep going run the heater on max and suffer, but you won't kill the car.

Mike Frye

Does the '82 have a trans cooler built into the radiator?

If so, I think the design in general was probably pushing the limits of what a radiator can be expected to do in 100% clean original condition.

Add 30 years of deposits (inside and out) and it's not going to be exchanging heat as efficiently.

The oil cooler on one side and the trans cooler on the other, both adding heat just means it's too much.

I hear you on the fan, but I think I'd probably take the rad to a shop and have them clean it up inside and out.

Nothing is broken until it's clean and broken...

MikeinBloomfield

Mike, I think that's my next step. Have a radiator shop do what they can. After that I'll look to replace.

depami

Does the electric fan run?

Last summer I ran my '82 for a couple weeks with no belts. At speed things were normal but in town the gauge would start to climb and the electric fan would turn on. I don't know if the e-fan would have been enough as I got the heck out of Dodge and back to speed. By the way, that is the only time I had ever seen the e-fan run.

On a side note, I had the same problem as yours with my Supra which I solved by pulling the radiator and cleaning out about five gallons of mayflies (15 years of driving around lakes).

dcrasta

Try cleaning the radiator especially between the AC condenser and Radiator.

IF that doesnt work you may want to flush the radiator. Safest way would be to take the radiator out of the car, and using a weak solution of water and CLR (Calcium/Lime/Rust) flush the radiator. There may be scale or calcium buildup (from using tap water in the radiator) that can coat the inner surface and inhibit heat transfer. Even if its not 'clogged' the calcium buildup can act as a thermal insulator.

Also, your lower pan (the front pan) and the fan shroud have impact on the cooling efficiency. IF you do not have them installed properly, it affects the low speed airflow , and air can spill past the radiator under the car. This is not as big a problem at high speeds, but especially in the bumper to bumper crawl your shroud can make a 20-30 degree difference.

I would try both solutions before taking the radiator to a 'shop'.. The shop will either do a chemical flush (which you can do with the muric acid/CLR flush) or a 'rodding' where the remove the endtanks and push a physical rod (and Im not sure the rodding can be done with our radiators ..).

928nut

Sorry Mike, I disagree - if you don't have a problem when moving it is simply insufficient air flow, nothing to do with your rad. I fought the same battle for years trying everything under the sun to no avail. Few years ago I decided to ditch the A/C and pulled everything associated with it out, including the condenser. Magically, my overheating problem disappeared and it is A1 to this day.

Now you may not want to ditch your A/C so I would suggest, throw out the mechanical fan and install dual electric puller fans. That should overcome the airflow problem.

hacker-pschorr

+1

I'm in-between a project of ditching the belt fan in favor of S4 electric fans in my 79. I've driven it quite a few times without any fans, no issues unless I'm stopped for an extended period of time (any normal stop light rotation isn't an issue).

No A/C condenser or coolers in this car.

Lizard928

Your viscous fan fluid is gone.

Replace mechanical fan or convert to an electric unit!

Imo000

Don' t get an aluminium radiator!!!!!

James Bailey

First the sending unit for the temp guage may not be accurate. It has two signals a variable one for the gauge and an on off switch for the idiot light. The 82 has a pusher fan STOCK it turns on when the A/C is working AND the thermal switch in the left end tank front near the bottom SHOULD turn on the fan when you hit about 2/3rds on the gauge IF the gauge is accurate.
You also should check if all the warning lights are working ?? when you turn the key switch before starting the dash should light up. It is possible that your warning was from low oil pressure so see if that warning light is working.
Often there is a lot of crude debris between the condensor and the radiator which limits air flow.
If you did not have any coolant loss boil over when you shut it down it may NOT have been all that hot. If you have access to a infrared thermometer you could do some temp checks.

RPetty2

My car started to over heat on highway, long story short Kibort found that the flaps in front were closed shut giving me no air, I yanked that **** out and fine now, Check that too!

Lizard928

1982, no flaps