air conditioning related to cooling fan

[carls]

Have been having trouble with the air cond'g shutting off when the temp gets above mid 80's. Hot summer days, highway drives. Had it serviced at local shop and they added freon and said it checked out ok. It works just fine below 85 deg. but shuts off above that. Its my understanding that the engine cooling fan must come on with the air conditioning. So in my driveway I checked if the engine fan does run with the air on, it does. Thats with the fan on low speed and barely audible. This summer I have noticed that the fan doesn't run on high speed anymore when I come home on a hot day where it used to. Could these two things be related? Like maybe the high speed fan function isn't working and so the a/c doesn't either when the ecm demands high speed? 2001, volvo v70 xc 150k miles. thanks CS

[hoonk]

There is an ac pressure switch that will turn the compressor off if the pressure is too high (or low). If the radiator fan does not work properly the pressure can get too high - or the switch could be turning the compressor off at the wrong time - so that is a possibility -

You might be describing the common worn ac clutch/too large a gap for the clutch to stay engaged when hot problem. If the ac works normally (is cold) and then suddenly stops cooling when it is very hot outside, and the compressor is not engaged when is it not cooling - the clutch gap may be too large. Once the compressor cools down the ac blows cold again. It's solved with a new compressor or some have been successful with removing shims from under the outer clutch pulley, to decrease the gap.

The next time it does it either check power to the compressor with a test light (hard to get to/hot down there!) or take a long pry bar and carefully give the outer pulley on the ac clutch a nudge, to help it engage. If it has power (and is not engaged) or engages with a push you have the answer.

[pelagikos]

Most likely, AC clutch - gap too large. Fixed mine a couple years ago by removing the plate and discarding one of the shims.

[gwee]

When idling little or no air flow arcoss the condensor will cause the AC to shut-off due to high pressure. My suggestion is to check the condensor and clean it.

[guymon]

Their is a AC clutch fix (hack) called the "bread clip solution" that is a common thing to do, in fact I think I need to do it soon. I suspect the fix will get you by another couple years, until the clutch needs replacing. You can search the forum here for specifics on this hack.

[pelagikos]

Their is a AC clutch fix (hack) called the "bread clip solution" that is a common thing to do, in fact I think I need to do it soon. I suspect the fix will get you by another couple years, until the clutch needs replacing. You can search the forum here for specifics on this hack.

I did make an attempt to pick a radial retaining ring that would fit instead of bread clips. No luck.

[Astro14]

The bread clip fix is a jury-rig...not a fix.

I had the same problem this summer with both P2 cars: AC works for a while, but the hotter the outside air temp, the shorter that time (naturally...and when it was 95 degrees here this summer, with similar humidity, the AC ran for 10 minutes...so, it was time to take action) and the AC compressor clutch won't engage again until nudged or until it cools off. Note, low freon yields the same symptoms, so have that checked before proceeding.

The real fix is adjusting the compressor clutch gap. It should be between 0.016" and 0.020"

When I measured the clutch gap on the XC, it was 0.032". The T5 turned out to be the same.

You can remove the compressor clutch plate with an AC compressor tool while the compressor is still in the car. No need to discharge/recharge the system.

1. Remove the accessory drive belt and intercooler plumbing on the front of the engine for access. I removed the charge air pipe over the top of the engine, including the charge air pipe to intercooler hose, as well as the intercooler to throttle body pipe.

2. Unbolt the compressor, four bolts, and move it towards the center of the car a few inches to gain access.

3. Using an AC compressor tool, loosen the 10mm bolt at the center of the clutch

Tool detail

I bought mine here: http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1 for about $65.

4. Use a puller that threads into the clutch plate to remove the clutch plate. There are three threaded holes, likely plugged up with compressor material/dust from years of wear, into which you thread the puller. Puller shown on bench for clarity. Note the 3 bolts threaded into the holes on the clutch plate.


5. Carefully remove the plate. Here is the compressor with the plate removed. Not a lot of room in which to work, but with the plumbing removed, it's enough. You can see that the compressor is moved an inch or two towards the center of the car, just enough to get the puller in there. The AC lines are flexible enough to remain connected.


6. On the bench, remove the shims from inside the shaft. Get a good reading on their thickness. In both of my cars, there were two shims, one was 0.003" and one was 0.032". So much for just pulling out a shim, I had to reduce the overall shim thickness by 0.016" to 0.012" to get my measured initial gap of 0.032" back into specs. I tossed the thinner shim into my "odd parts" bin. Searching parts and fastener stores did not yield any useful shim substitutes. Commercially available washers were all far thicker. So, I lapped the remaining shim down to a thickness of 0.020" on a diamond plate. being careful to keep the thickness consistent.


7. Assembly is the reverse of removal. Use the 10mm bolt to pull the clutch plate back onto the compressor. Bolt the compressor back onto the block. Re-install plumbing and the accessory belt.

Enjoy your new AC...and the $1500 you saved by not having a new compressor installed.

[pelagikos]

As matter of fact (I have done this myself) if you have enough patience and want to get a little creative , you can remove/reinstall the clutch plate without unbolting the compressor, messing with the belt, etc. and without any specialized tools.

I did not make notes and am a little fuzzy on the specifics (3+ years ago), but the gist is:

*Thread in 2 bolts (from a hardware isle) into 2 of the 3 threaded holes on the plate.
*These bolts and a wrench can serve as a counter-hold for removing the center bolt.
*Once the center bolt is out, thread in another bolt in the 3rd threaded hole on the clutch, and continue threading the 3 bolts in (each a bit at a time) until the plate pops off.
*Remove the shims (I had two, discarded one, ground another down a bit on a sheet of sandpaper)
*Reassemble using the same technique for tightening the center bolt (two small bolts and a wrench as a counter-hold)

Worked well for me. 3rd summer is almost out since the fix.

[guymon]

Astro14, nice writeup! Has anyone used on of the AC clutches or repair kits I see for sale on eBay.

http://www.ebay.com/itm/Volvo-XC90-A...dc2839&vxp=mtr

This one is for an XC90 but did'nt know if it would work for a XC70.