How would I check a fan clutch?
 

What is the easiest way to check a fan clutch? I can easily turn it by hand when the engine is off and hot. When running and I shut the engine down the fan stops without even making 1 complete revolution.

I am having some A/C issues and think I am not getting enough air flow thru my condenser. I am thinking the fan clutch could be bad.

Thanks, enjoy the Holiday
Frank D

When it's cold it should spin freely with the engine off, and it should be stiff when the engine is hot. What year van? It may be losing freon...

I just replaced the evaporator, it was bad. No leaks at all now it took a 3.5lb weighed charge of R-12, I have a few lb left over from many years ago (father in law). A/C blows cold when at a fast idle, hot slow idle. If I run the garden hose over the condenser the A/C will blow cold at a slow idle. It doesn't overheat.

When the engine is hot the fan turns easily by hand. Honestly I didn't try turning it when its cold: YET, I will do that in the morning. 1988 e-150 4.9L. When I turn off the hot engine the fan stops spinning in less than 1/2 a revolution.

Thanks
Frank D

make sure the condencer is clean.
what kind of pressures are you running? did you check for leaks with a micron gauge?

Answers to ????/from Crash687. All help is appreciated
 

Thanks for the reply Crash687,

This thing is driving me nuts! System held vacuum for 4 hours, we charged it, tested for leaks with a sniffer, no leaks, also used soap etc. Its holding a charge for 3 weeks now.

At 550-600 rpm idle 60lb back pressure, 125lb high. At fast idle 1500 rpm 44lb back 225 high.

(If I run the garden hose over the condenser idle pressures are about the 44/225 reading).

I watched 3 fan clutches on 3 vehicles yesterday and mine is working exactly the same. The Condenser looks clean, I did not clean it (I will try that).

I am in the process of replacing the engine thermostat and going from a 195 to 180 degree (Figuring it would cool the engine compartment, radiator etc.)

Next step: I am thinking of putting a push fan in front of the condenser, in addition to the stock clutch fan to aid in cooling the condenser. The vehicle doesn't overheat now.

I also checked the little oil that was still in the bad evaporator, it was perfectly clean, and there are no compressor noises.

I am looking forward to hearing from you, thanks for the reply!

Thanks
Frank D

the low idle readings indicate possibly bad valves, but the part with the pressures rising when cooling off the condencer makes me wonder if there is air or moisture in the system in the system. did you replace the desiccant when you replace the evaporater. you may have to replace the metering device and change the oil also.

More info, thanks Crash!!
 

Crash687 Said:
did you replace the desiccant when you replace the evaporater. you may have to replace the metering device and change the oil also.

I did not replace the desiccant, or metering device, (accumulator dryer etc.) I added 2 oz of fresh oil to the system when we had it pumped down.

The system was open for about 2 days while waiting for the evaporator to come in, (had to be ordered). We did evacuate the system, once the repair was made, I guess moisture is a possibility.

I had the van out today, was in the low 80's and it seemed to be working well, but only went for about a 20 minute ride.

I would hate to drop a full charge of Freon :-huh

Thanks
Frank D