running hot in traffic

[hemimets]

I have 72 challenger with factory ac, south Louisiana heat. Temp is fine when moving but as soon as I hit any traffic temp comes up quick. I had the 26" radiator checked, its fine so is the fan clutch. Wanted to try trans cooler but scared to mount it in front of radiator cause of the blocking air flow issue. Is my only option an aluminum radiator and electric fan? any suggestions?

 

[moparleo]

Make sure to use a shroud and a thermostatically controlled electric fan instead of your mechanical fan is the best option. Manual fans are not used any more because of their better efficiency, no horsepower draw, and no chance of cooling system damage if you lose a fanblade.

 

[Chryco Psycho]

That's odd , I lost a fan blade a couple of months ago , electric fan in a Caravan , it totaled the rad !!
A lot of electric fans are far less efficient than engine driven ones , most cars these days do not have the huge engines used in the old days so they will get by with a small electric fan . You need good water flow using a HV pump & the other factor is air flow Out of the engine compartment , often a big block with uncoated headers will have a lot of hot air trapped under hood , on one build we had to add air vents to the hood to allow air flow out . shrouds make a huge difference in the cooling efficiency .

 

[Adam]

"Temp is fine when moving"... That is a big clue, I would suspect the fan clutch, it may look ok, but how can you tell how much it,s slipping? Try a solid spacer to test it out.

 

[hemimets]

I took the fan clutch off and spun it by hand and compared that to a new one at the parts store. No diff between the two. Explain the solid spacer test please.
I have uncoated headers so im sure there is plenty heat in the engine compartment. Anyone running an electric fan they could recomend?

 

[burntorange70]

Do you have a shroud? Also how far is the fan blades from the rad?

 

[hemimets]

Yes. Factory shroud I believe. Fan is really close to radiator

 

[moparleo]

Electric fans can be either mounted in front of the radiator to push air through the radiator or behind the radiator to pull air through. Another plus is that it will flow more air through your a/c condenser at low speeds increasing the a/c's efficiency. No horsepower loss and they can be operated with the engine off. Naturally all fans are not necessary over 40 mph as the air forced though the radiator exceeds what the fans are designed to flow. My fan story is last year the clutch fan exploded at 40 mph in my BMW 750IL . 15k damage to the maf's( it has 2 of everything, V-12) air boxes, wiring harness, radiator, tank, as well as major hood damage caused by the fan blades trying to exit the car. BMW replaced the manual fans for electric fans the following year. The positive thing is that I took the insurance money and bought a 2006 Dodge Magnum R/T Hemi powered wagon. I love it.
The point is, there are pluses and negatives for every thing you are looking to do. Make your choice and pay the man.

Oh hemimets, I believe the purpose of the solid spacer test is to see how much air a solid spacer verses a clutch type fan will flow.

 

[Adam]

I do not think your hand can compare to the resistance of a fan, even at idle. About 12 yrs ago I had a similar issue on my 70 Cuda; one time when it was getting real hot I opened the hood and looked down at the fan. It seemed to be going just a little slower than the engine speed. I do not recommend this but I put my fingers behind the fan to feel the air output, then I let the trailing edge of the fan blades slap my fingers. It began to slow down and then stopped, even though the engine was running! This was a HD clutch unit for an AC car which I bought new, but had left sitting on my shelf for at least a year. I have read this allows the fluid to run out, although I didn't see any. I replaced it with a Flex fan and solid spacer. It put out a ton of air and certainly cost some HP, but it was less expensive than going electric. If you get a Flex fan get one rated for high RPM for peace of mind. And yes I still have all my fingers.

 

[burntorange70]

Ya I don't know if there is a safer way to check and make sure the clutch fan is good or not. Starting to sound like it is bad. You can go out and buy a new aluminium rad and electric fan but if all you need is a new clutch thats a lot of money spent to fix a simple problem.


So does any one know how to check a clutch fan to see if it is good or bad and not cut off all your fingers?




Could just put on a fixed fan (if you have one) and see if that helps.

 

[hemimets]

Changed fan clutch earlier today. Heading to cruisin the coast on thurs. We will see what happens. Thanks for all the help guys

 

[Chryco Psycho]

A clutch fan will tighten with heat so when it is cold it should free wheel so comparing to one on the shelf @ room temperature is useless , the clutch operates with heat so as the fluid swells it will lock the clutch increasing air flow . I have found a properly working clutch to be the most efficient for cooling .