2002 S60 AC blows cool air for a while (between 20-60 min) then stops blowing

[chrism]

This sounds to me like a classic case of clutch wear, needing the famous "bread clip" or "zip tie" fix. I have done this repair 3 times for exactly the kind of symptoms you discuss. The clutch plate wears, so when it engages, the spring is pulled harder. The electromagnet gets hot during operation and therefore loses some of its power, the the springs pull the clutch off the compressor. When it cools down a little, it re-engages. The bread clips or zip ties act as shims pushing the clutch a little closer to the compressor, compensating for the wear, and making the electromagnet more likely to overcome the spring tension. Simple fix. Even if this doesn't fix your problem, it won't hurt, as your car is at the age where the clutch is clearly worn. I don't have a link to it but search this forum for A/C Bread Clip fix and you'll find it. Good Luck!

hansenjg, it seems to me the problem is not that the compressor isn't doing its job. From the sounds of it, so far, is that something is restricting the blower from pushing air into the cabin. And it's a restriction that occurs gradually, all the while the air that IS coming out of the vents (or TRYING to come out of the vents) is still cold, which wouldn't be consistent with a failing compressor clutch. Hey, I've been wrong before......

Code9, if the car is running with the AC on, open the hood and listen carefully over by the AC compressor. If it's cycling, you will definitely hear a fairly loud "clack" when the compressor engages and a slightly quieter "click" when it disengages. Also, if you watch the center "hub" part of the compressor pulley, it will start turning and stop turning in sync with the click and clack.

[coded9]

Code9, if the car is running with the AC on, open the hood and listen carefully over by the AC compressor. If it's cycling, you will definitely hear a fairly loud "clack" when the compressor engages and a slightly quieter "click" when it disengages. Also, if you watch the center "hub" part of the compressor pulley, it will start turning and stop turning in sync with the click and clack.

Ah ok, I see what you're meaning there.
From what I've noticed I'd say it ran constantly until it quit. I've only heard it going through the motions when i switched the ac on or off.

[chrism]

If it's producing cold air yet not cycling, that REALLY suggests a faulty evap sensor.

[coded9]

If it's producing cold air yet not cycling, that REALLY suggests a faulty evap sensor.

I went ahead and ordered that sensor from fcp last night. I'll keep posted on whether that does the trick. I wasn't sure what is "normal" behavior for these AC units (It's probably been this way since I bought the car).

[coded9]

Ok so I finally had a chance to test the ac, had another long drive. The AC system worked without fail, got cold air consistently the entire time i used it. Heck, my gas mileage was slightly better because it didn't run the compressor so much!

I thought it might be worth noting I thought to test the new sensor before installing, old one was in the 450 ohm range at about 90 degrees F, the new sensor had 3X that amount roughly so i figured hey i did something right. I might do the clutch fix if i start getting issues with that, rather not risk it until it's broken. Plus, still learning how to jack the front of the car up

[oragex]

Do you have a more precise resistance value at 77F? I expect them to be around 1.5-2 Kohm. I purchased a 2.7 K ohm @77F and I have the clutch cycling less often (still like it, it is not ice cold, just cold and comfy)

[coded9]

Do you have a more precise resistance value at 77F? I expect them to be around 1.5-2 Kohm. I purchased a 2.7 K ohm @77F and I have the clutch cycling less often (still like it, it is not ice cold, just cold and comfy)

Not off hand, though I could try to measure tomorrow morning when the low is 77. I just recorded that one at 90 before putting the sensor in. With the new sensor it's not ice cold as much as before, where it was constantly ice cold.