[rdj]

I think I am at a point where I could use some expertise from fellow members. It's a 2005 Touring.
Here's what's been happening consistently for a week now:

A/C turns on and cools normally for about 10 mins. Then, the A/C clutch lets go for unknown reasons and compressor disengages, never to kick in again. I turn off the engine, wait about 20 mins, restart the engine, and the cycle starts all over again.

A few observations I noted:
-When clutch lets go after 10 min of operation, the display still shows "A/C ON", clutch relay is energized, and relay contacts do show 12V (which means the stator must be activated). The relay seems fine and when I place a jumper wire between the contacts, clutch still does not engage.

-At the beginning, I read the stator coil resistance to be about 5 ohms. When clutch disegages after 10 mins of operation, I find the resistance to have climbed up to megaohms. Then I turn off the engine and start waiting, I see the resistance slowly go down to 5 ohms, at which time the clutch becomes operative again.

-The engine temperature seems to have nothing to do with this cycle. The A/C operates for about 10 mins regardless of when I actually start it. In other words, the engine may be very hot when I start the A/C. it will still work for ~10 mins. So, it must be something happening in the clutch/compressor that controls this cycle.

It certainly sounds like there is a kind of protection element in the clutch assembly, which under abnormal conditions, such as compressor seizure for example, somehow cuts off the stator supply and disengages the clutch. However, I have gone through all the related threads and haven't been able to verify this.

What do you think the problem might be?


Thanks in advance!

 

[rdj]

I guess nobody has any idea????

 

[rdj]

Thanks Cnn for the very useful info, though it comes a little too late for me......
I finished the stator replacement a few days back.

I worked on it for 2 days, 2.5 hours per day.
I would say, I spent a good 4 or even 4.5 of the total 5 hours on removing and installing the circlips! Such a pain... I was hoping getting them on would be easier but nope. There is simply not enough clearance to maneuver the hands and the tools.

The good news is A/C is now 100%!

The clutch and the bearing were in excellent shape, so I didn't replace them. The clutch gap was originally 0.65 mm. I used the exact same shims, so the gap is still 0.65 mm.

I put the vehicle on ramps with wheels turned fully right, and worked from the passenger wheel well. I leaned my head and upper back to the inside of the wheel, used an old crib matress to make it more comfortable and a portable light.

While there, I replaced the accessory belt, oil/oil filter, air filter and I did some small paint job on the front bumper while waiting for the new stator. (Paint job is not included in the 5 hours).

 

[rdj]

I had replaced my stator coil exactly 2 years (or 12000 miles) ago (May/Jun 2012 - see post #103 above). The problem just came back about a week ago. I wonder if the season has anything to do with this stator failure...

Anyhow, I decided to replace the stator coil once again (this is my #3 including the factory coil), but this time I unbolted the compressor and worked from the front of the vehicle. I had to remove the short cross brace to allow access from the bottom. I put the van on ramps and I lay flat on the ground while working. I found this method easier than working from the wheel opening as in my previous work (post #103). Removing and installing the circlips were notably easier because I was able to position the compressor for the optimal angle. I used a HF tool with 45-degree tips attached on only 1 side (cnn's method). Now the A/C is back to 100% again. This is the good part of the story.

Now the not-so-good part: I fear that this fix will not last long... The reason I say this is because this time I found oil on the stator coil and parts of the clutch, which probably leaked from the compressor's front shaft seal. I wasn't anticipating a compressor replacement, so I just did the coil fix to get the van up and running quickly. I do know the leak will kill the new stator coil in short order by causing the clutch to slip and eventually tripping the built-in thermal fuse. If I used the one without the thermal fuse, the leak would then kill the clutch itself. I should plan on acquiring a new compressor...

I hadn't logged on this forum for a long time. When I did last night, I saw lots of new information posted since my last visit in 2012, (especially by cnn). This thread is really a gem for anyone who wants detailed information before attempting to do this themselves. Thanks to everyone who spent the time and effort to share the information and their experiences!