overheating at low speeds and idle

[drhill]

What have you guys done to get rid of any overheating issues at low speeds and idle? I live in a hot desert climate and the coolant temps steadily climb if I sit with the engine running for any length of time. There seem to be no severe duty fan clutches. I even added two Toyota Corrola pusher fans in front of the condenser and these seem to just slow down the inevitable.

I hate to switch to a full time electric fan but maybe that's the only choice? all my cooling system parts are new, big aftermarket aluminum mustang radiator, new water pump, new fan clutch, shroud is good etc...

Thanks for any ideas

[t65neon5]

did you buy a new radiator cap?.......a bad cap can cause this...also, a good oil cooler couldn't hurt, you could go direct drive with the fan, or get a non-thermal fan clutch.not sure what car you have, but if its a 302/351...you can get a severe duty fan clutch(non-thermal).....just have thenm look up a 351 police fan clutch, hayden makes a non thermal ...part#1710, and is good for standard or reverse rotation

[BigT]

I upgraded to a 3 core radiator and use an electric fan. I adjusted the fan to come on more during the summer than the winter.

[sly]

you may also want to switch to a 185 degree thermostat or just replace it if it hasn't been done yet. The original thermostat may be sticking or not opening enough.

[drhill]

Thanks for the thoughts guys. I did do the 185 t stat and it does seem to work really well. a little slow to react sometimes. Also I did a new cap when I got the new radiator 2 years ago.

I always thought the non thermals didn't cool as well as the thermal fan clutches? It would be a cheap alternative to a reliable e fan setup if it's in fact better at cooling. Direct drive is an option for around town, unfortunately it would kill mpg on a highway trip.

I looked up fan clutched for the 351w police cars...same listings as the standard cars There has to a severe duty clutch made for our cars, right?

[sly]

check other years (up to 91) and see if there's any "police/taxi" or severe duty ones listed. I'm pretty sure there's one out there. It may also be listed for 302 trucks though and I'm not sure that those will actually fit, but they might. I do know that I've head of caps and t-stats going inside of 1-year so you might need to check those. I'd check the fan clutch first though, as that's a simple fix not requiring any fluids. If the fan keeps freewheeling after turning the car off when it's at operating temp, the fan clutch is dead. you can also check the resistance manually with the car off as well. Check it when cold and it should move pretty easy. Then check again when warm after just shutting off the car and the fan should be much stiffer.

[drhill]

check other years (up to 91) and see if there's any "police/taxi" or severe duty ones listed. I'm pretty sure there's one out there. It may also be listed for 302 trucks though and I'm not sure that those will actually fit, but they might. I do know that I've head of caps and t-stats going inside of 1-year so you might need to check those. I'd check the fan clutch first though, as that's a simple fix not requiring any fluids. If the fan keeps freewheeling after turning the car off when it's at operating temp, the fan clutch is dead. you can also check the resistance manually with the car off as well. Check it when cold and it should move pretty easy. Then check again when warm after just shutting off the car and the fan should be much stiffer.

Cool thanks. I actually just ordered a new old stock motorcraft fan clutch off ebay...yb-327, supposedly a discontinued police HD fan clutch. It doesn't seem that anyone makes the HD clutch anymore. I'll see if it's any stiffer when it comes in. My current clutch is working as designed...I bought a new replacement and it was exactly the same resistance under differing conditions so I put my old one back on and returned it!

Cap is cheap enough so it's worth replacing just in case. The t stat is working fine as it it has plenty of flow...stays near 185 or 190 once the car is moving...even on 110+ degree days.

[TrapSpeed111]

If anyone needs high flow water pumps for our cars Amazon has them for $50. the price and quality is unbeatable http://www.amazon.com/GMB-125-1700P-.../dp/B000JYHHU8

[BigT]

If anyone needs high flow water pumps for our cars Amazon has them for $50. the price and quality is unbeatable http://www.amazon.com/GMB-125-1700P-.../dp/B000JYHHU8

Nice!

[gadget73]

Something seems wrong. If you're moving that much air across a large radiator, it should not be overheating at idle. The engine isn't doing much work just sitting there chugging along. The clutch fan plus a pusher fan ought to be plenty sufficient. No chance that the radiator is starting to crust up internally from crappy water is there?

All else failing, I believe the truck fans have more blades. I also seem to remember bolting a fan an clutch assembly off a late 70s Lincoln with a 460 onto a 302 in a Grand Marquis in an emergency. It sounded like a helicopter at idle, but it moved a crapload of air.


Oh, dumb question, but you do have the fan shroud in there right ? It needs to be present for the fan to be effective.

[drhill]

Something seems wrong. If you're moving that much air across a large radiator, it should not be overheating at idle. The engine isn't doing much work just sitting there chugging along. The clutch fan plus a pusher fan ought to be plenty sufficient. No chance that the radiator is starting to crust up internally from crappy water is there?

All else failing, I believe the truck fans have more blades. I also seem to remember bolting a fan an clutch assembly off a late 70s Lincoln with a 460 onto a 302 in a Grand Marquis in an emergency. It sounded like a helicopter at idle, but it moved a crapload of air.


Oh, dumb question, but you do have the fan shroud in there right ? It needs to be present for the fan to be effective.

Yep - fan shroud is present! but since my radiator is for a fox body car...i have the matching shroud. radiator performs very well under load, at speed, in 120 degree heat...etc. but idleing for more than a couple minutes in 115 degree heat with AC on...forget about it. Slow climb to 210...215...220...225...and that's usally when I shut the ac off.

Condenser and radiator fins are not clogged and in good shape. I am definately asking a lot of this car. I've had near new Mark VII's and 5.0 Mustangs that can't handle this heat at idle either. They have a severe duty fan clutch option that really helps reverese rotation WP cars...also, the Mark VIII fan I have in the garage would solve the problem but i've had e fans quit on me...no fun.

[gadget73]

Maybe a booster fan in front of the radiator, and keep the mechanical fan as a backup. If there is room, you might try a fan out of a mid 90s panther. They had both an electric and a mechanical fan. E-fan ran with AC and overheat. The electric fan sat between the mechanical fan and the radiator.