440 Overheat at low speeds.

[Mattfi1]

Hi, I have a 68 GTX that will overheat in stop and go traffic. I notice that the clutch fan is very loose when not running and I think it may not be spinning enough at low RPM's. Has anyone changed one out for a different type say non-thermal clutch?

 

[mosquito13]

Not on a GTX but my ford van. I added a pusher fan on the radiator. I tow a car hauler from FLA to Tenn. and the Atlanta traffic and mountains in Tenn. were pushing the cooling to the point I would have to run the heat on high with full fan. Now I flip on the pusher fan from a dash switch and leave the a/c on. Lighted switch so as to remind me to turn it off when speeds increase.

 

[rlem1977]

Hi, I have a 68 GTX that will overheat in stop and go traffic. I notice that the clutch fan is very loose when not running and I think it may not be spinning enough at low RPM's. Has anyone changed one out for a different type say non-thermal clutch?

How long has it been doing this? If you didn't have an overheating issue until recently, and it is the fan clutch, why change out for a different one? Just replace the stock one.

 

[max340]

Not on a GTX but my ford van. I added a pusher fan on the radiator. I tow a car hauler from FLA to Tenn. and the Atlanta traffic and mountains in Tenn. were pushing the cooling to the point I would have to run the heat on high with full fan. Now I flip on the pusher fan from a dash switch and leave the a/c on. Lighted switch so as to remind me to turn it off when speeds increase.

Could be a bunch of stuff. Timing, fan shroud, thermostat, clogged radiator, too small of radiator, etc.

 

[moes]

low speed over heating is caused by an airflow issue. Is the fan blade half in and half out of the fan shroud? Make sure the air flow being directed into the rad to and not around it. I agree what max340 said to and I would check your clutch fan to see if it's working correctly .

 

[Dennis H]

Replace it with a Hayden thermal.

 

[65-440]

All of the above .... the fan clutch should have a good amount of resistance , should not free spin

 

[Mattfi1]

Thanks all, I think I'll just get a original replacement. The car was completely restored last year to new condition and the radiator was re-cored with three rolls. The clutch is the original factory one. It does spin quite freely when not running. Its still in storage but I'll be getting it out next week if the snow stops.

 

[snakeoil24]

Rock Auto has a replacement Hayden for 50.00

 

[65-440]

I got my clutch from Napa, told them 70 coronet w/ 426 hemi. Heavy duty clutch ... def pulls some air that's for sure. Can't recall the price though

 

[snakeoil24]

Still cheaper than blowing up the motor

 

[mopar73dge]

replace with a new one it should not be that loose, my 2 cents

 

[Tim Chavez]

Oh simple fix! Just increase speeds!

 

[Ccas]

Thanks all, I think I'll just get a original replacement. The car was completely restored last year to new condition and the radiator was re-cored with three rolls. The clutch is the original factory one. It does spin quite freely when not running. Its still in storage but I'll be getting it out next week if the snow stops.View attachment 597085

That clutch should spin pretty freely when cold. But if you turn off the car when it is really hot, it should have some decent resistance. I'd say that replacing that clutch will absolutely help. If it doesn't bring temps down as much as you want, then some of the suggestions above are worth looking into.

Also and either way, I would seal the perimeter of your shroud all the way around. You can use any black foam weatherstrip and basically trap the weatherstrip between the shroud and the radiator. That will create better air velocity through the radiator. It also can be done where it's quite unnoticeable.