2nd Gen Non-Engine/Transmission Idle/Low vehicle speed....no A/C

[sheamc]

I recently had the system checked and re-filled with refridgerant and a leaky valve was replaced at the same time. Having been without A/C for a while I notice that when at idle, not moving the a/c goes to pot. As soon as the vehicle starts down the road at anything other than a crawl it cools right down, and quickly. Could this simply be the fan not drawing enough air? This I assume would be a clutch/hub replacement but don't know enough about the A/C system to trust my diagnosis. Thanks for the help guys.



Shea

 

[Nigel]

Take a peek between the inter cooler and the rad. I'll bet you will see the front of the rad is caked with dirt and therefore you get no airflow across the condenser at idle. With a garden hose try flushing some of it out from the fan side and you will be cold again.

Nigel

 

[DavidC]

What Nigel stated could be your problem or it could be your fan clutch. If you do not have adequate air flow the clutch on the compressor could shutoff from the AC high pressure switch and while moving you have enough air flow to keep the refrigeration pressure in check.

Dave

 

[klcammie]

I agree after I pulled rad and cleaned it was like a new ac. cleaned after cooler and cond. at same time. lots of air flow then.

 

[B.G. Smith]

And if that don't do it, check and see if your vacuum pump is working, should be at least 17 inches. bg

 

[KRStone]

And if that don't do it, check and see if your vacuum pump is working, should be at least 17 inches. bg

Thats what i am thinking (if not radiator) could be vacuum leak not keeping blend/control doors in correct spot.

when my vac hose had a bad keak, it defaulted to defrost at idle, see if yours does that at idle.

 

[HHhuntitall]

The old thermostat in my '97 wouldn't keep the water hot enough to keep the clutch fan engaged at an idle, so when the fan clutch isn't engaged, the A/C headpressure goes off the chart and the high pressure switch kicks the compressor off. I fixed it with an electric fan, which works great, especially when leaving it idling with the kids in it and the AC on when I'm getting gates and such driving in the pastures, or driving slow hauling hay or such. I just have it on a toggle switch.

The washing of the front parts is a bi-annual thing around here. Grass, leaves, and dirt get sucked up in there and has to go to keep 'er cool!!! I usually soak it down in engine degreaser, let it sit a bit, and then wash it out good, working both ways a time or two. Really helps summer cooling when ambient gets up over 100*..... Lowers intake air temps, reduces the time the clutch fan runs, and helps the AC work more efficiently.

 

[klcammie]

glad to hear you fixed and running.

 

[DavidC]

glad to hear you fixed and running.

 

[klcammie]

read it wrong I thought the guy fixed it. teach me to write without reading whole post.