RedRocket

I have had nothing but A/C trouble this week!!! Anyways, my A/C will not blow cold air at idle. I don't know if the compressor is cycling or not. What are some areas I should check?

nitrousn

make sure the condenser is clean and will let air pass through. watch the compressor and see if the clutch kicks in. if not jump the LP switch.

thumper 549

your fan thing probly is not holding......fan no twirly

scuzman00

Thumper may be on to something, the fan clutch may have lost its viscosity and is free wheeling and not moving enough air. Have a buddy rev truck up to 2200 RPM and kill engine while you watch fan. If your fan spins more than 5 revolutions when engine is shut off, the fan clutch has gone bad. Running it long like this can eventually wipe out the internals on your compressor (from past experiences GM compressors tend to scramble their innards).

Keep us posted

jthorpe

On my Ford, this happened when my fan clutch went bad. I would have it checked.

RedRocket

I replaced the fan clutch about 7 months ago. I don't see why it we have gone bad already. But I will check it out. Thanks for the info. Kevin

Bill Tomlinson

Even when the clutch fan is fine, they don't usually kick in soon enough. Diesels run pretty cool at idle and the fan does not engage much. I am thinking about some kind of skinny fan to force air over the condensor at low speed. No problems above 35 mph. I was also amazed at how quickly the ac overheated just a minute or two after a cold start. It makes sense though. Why would the clutch fan engage then? Until you get a fix, shut off the ac when stopped or something expensive may get you.

scuzman00

The fan clutch actually diengages and "free wheels" at higher road speed. It actually turns faster when the engine Idles. Sometimes when you start up engine and take off at a quick clip you can hear the cooling fan roar fairly loudly and then around 2000 rpm the roar goes silent. This is because the fluid in the clutch becomes less viscous and allows the fan to free spool somewhat on the shaft. Usually when you are running in the 2000 rpm range the truck is moving fast enough to provide airflow across the condenser to satisfy the refrigerant cycle. Another simple way to check the operation of the a/c if the fan clutch is bad is to spray cool water across the condenser while the truck is idling and the a/c is on full tilt. If the a/c blows cold at this point, (where it does not usually) then you can almost be certain the fan clutch is/has gone south.

Gary

INJECTOR JACK

Mine did the same thing, I pulled down the system checked for leaks was ok, recharged and added a extra 1/2 lbs works great now.