New member, Stumped by A/C problem

[Toolguy942]

Hi all! I've read lots of threads, but just got around to joining. I haven't found a thread that describes what is happening to me so here goes.

I have an '01 Sport Trac w/174K miles on it and the A/C is giving me some grief. It cools fine if I'm driving or stopped for short periods of time, but if I leave it idling and run into the store or get caught in a traffic jam for more than 15 minutes without moving, the A/C craps out.

When this happened at Home Depot a few weeks ago (wife was in the truck waiting patiently), I got back to the truck, wife says the A/C is blowing hot air, I smell a "burning" smell, immediately shut off the truck and pop the hood. That's when I saw what looked like smoke coming from the front area of the compressor. Not sure if it's the A/C clutch going out and causing the belt to slip some (without squeaking) or what. There are no grinding noises, so I don't think it's the bearings. The fan kicks in when I turn on the A/C so I'm getting air flow over the radiator at all times. And if I turn the A/C off I can leave it idle all day with no "burning" smell.

I don't have any gages so I don't know what the pressures are, but if I can rent a set from AutoZone I can do that if need be. Any help you guys can give me would be great. Thanks!

 

[BrooklynBay]

Welcome to this forum! Did you ever add any freon with compressor oil?

 

[Toolguy942]

Welcome to this forum! Did you ever add any freon with compressor oil?

I haven't added any R134 because I figured it would be short cycling if it was low and it isn't.

 

[BrooklynBay]

You could add compressor oil without freon if that's the case.

 

[Toolguy942]

How much should I add? What is the logic for adding it? I mean, I understand that it's for lubing the compressor, but if I haven't lost any refrigerant I shouldn't have lost any oil should I?

 

[BrooklynBay]

They make small cans just to give it a charge. Lubrication won't damage anything.

 

[teal94gt50]

Don't just go adding oil and refrigerant if you aren't positive it needs it. Overcharging with oil or r-134 can cause other concerns and make it more of a headache for you.

Judging by your description, you more than likely have the coil for the clutch failing. They can overheat and cause the a/c to be inoperative, until they cool down, at which point they (generally) start to operate again. When they melt, they can also smoke/stink like you described.

The best way to tell will be to take the clutch apart and inspect the coil. Generally they will show visual signs of melting, sometimes they will not. Usually they will smell "burnt". Another way to tell on the vehicle is when it is acting up, with the vehicle turned off you can unplug the clutch, and apply power and ground to it on your own w/ a set of wires. If the clutch will not apply, or you get a large amount of sparkage/hot wires then you have a faulty coil.

Let us know what you find!!

Will