Strange AC Problems (and it's freaking hot)

kodebearkc · Post by **kodebearkc** » 22 Jul 2012, 21:03

Hello all,
I have a 2001 S80 2.9. I'm having the strangest AC problems, I'm hopeful someone here can help or has had the same issue.
My AC works perfectly when the ambient temp is below about 95. No problems. When it gets above 95 and right around 100 the Ac will work for a while then shuts off. When I say shuts off the compressor stops (everything in the cabin works fine). We all know the sound it makes when it's not running.

So I went and bought myself a set of AC gauges from Harbor Fright to better help me understand what's going on.

So here is what's happening.
Hooked up to the low pressure side (under the power steering/coolant reservoir) the pressure reading while the compressor is not cycling (running) is about +26-27 As soon as the compressor kicks on the pressure drops to about 0, it will kick on and off and each time the pressure climbs then drops when it comes on. I've seen it drop to as low as -5. but it seems to be about 0 when running and about +15 when not (cycling).

Is this thing just stupid low on R134 and when the ambient temp is lower the Gas is more stable or something? I know the charts say the pressure should be about 40-50 when about 100 degrees.

If it is just low and needs a ton of R134 is there a way to keep the compressor running so that it will pull the R134?

Also i forgot to say that when the Temp is high and it runs for a while then kicks off, i can turn off all the controls and after a few minutes of driving i can turn it on and it will blow cold for a few minutes before dying again. But i have to go though this process to get it to cycle again. This little procedure lead me to believe maybe it's a pressure switch issue but maybe not.

My stupid gauges can't fit down the area for the high pressure side so i have no idea what's going on on that side.

Thoughts?
help!!!!!!!!

Post by **jimmy57** » 22 Jul 2012, 23:23

The gauge readings don't agree with it cooling when it is cooling.
You're symptoms are exactly the ones for the compressor having too great a clutch plate gap when off. Wear increases the gap and when it is close to 1mm instead of the 0.40mm range of a new compressor, the electric winding used to create the magnetic force to pull the driven plate into the drive pulley face is too weak to do it. The heat of engine and of the winding getting warmer from use lowers the current flow in the electric coil and lessens the magnetic strength. Turning it off lets the winding cool off.
If you search "clutch gap" in the 2001 s60/v70/xc70 forum you'll find more answers as more of those cars are discussed.
There are a few ways to approach this, the most aggressive being to replace the compressor.

kodebearkc · Post by **kodebearkc** » 23 Jul 2012, 10:18

Thanks Jimmy,
I'll look into the Gap. The Temp thing and the Gap makes since. I'll read up on it. It looks like i need to replace the superinte belt anyways so maybe just replacing the compressor is the way to go. But i know that requires vacating the system and pulling a vacuum on the system to fill it.

trill2ride · Post by **trill2ride** » 28 Jul 2012, 10:30

Hey guys,

I am having the same problem and I have decided to fix it by using mechanic's wire. My question is after I am done what happens if the clutch gap is lower than the spec (.4-.3mm)? what if it is something like 0.2mm or 0.1mm? will that matter?

Thanks in advance.