'98 S70: 16 y.o. A/C system presents first problem

Post by **dosbricks** » 13 Jun 2014, 21:19

That's correct, since new, the car has never required A/C service or even additional refrigerant, and that's thru 16 South Texas hot summers. How could we not love a car like that?

But the A/C now cools fine for about the first 10 min. of driving and then the compressor shuts off for a couple of minutes allowing the interior to start getting warm. Then it will cycle on and run for several minutes until it repeats the same. It can sometimes be induced to come back on by moving the temp setting lower.

I have always associated low refrigerant with rapid compressor cycling, so I'm wondering if these very long cycles are indicative of another problem, although it makes sense that after this many years, low refrigerant would be the first suspect. My low pressure gauge broke last year when I used it on the 850 and I haven't replaced it. I'm undecided as to whether to invest in a set of gauges or just take it in for service. My knowledge of A/C systems is quite limited. Also, we have been pouring money into parts for these cars, and I have occupied my springtime with getting them up in top mechanical condition with still a bit more work to do.

Any advice would be appreciated.

dos

Post by **abscate** » 13 Jun 2014, 21:49

This is classic compressor clutch gap wear and if you search "bread clip fix" you will see the remedy

Post by **cn90** » 13 Jun 2014, 22:25

I use zip tie technique and it works fine.

Post by **jreed** » 14 Jun 2014, 05:35

Completely agreed. I had the same problem for the first time about three years ago on my '97. The symptom was that when accelerating the AC would shut off. I found the gap on the clutch had grown thru wear. I used cyanoacrylate (crazy) glue and brass shims on the clutch which have been holding up well so far. Zip ties seem like a better idea.

Post by **dosbricks** » 14 Jun 2014, 08:27

Alright! Three replies that agree on the issue. I'll do a search for the shim fix and measure the gap to see if it has grown wider than maximum spec--which would make perfect sense with the amount of use it has seen. I'll get on this next week and report back the results. Thanks for the help, guys.

dos

Vlvspd · Post by **Vlvspd** » 15 Jun 2014, 18:27

cn90 wrote:I use zip tie technique and it works fine.

Used some tiny zip ties and put a little epoxy on them 2 years ago, compressor is still running strong. I have had to recharge the refrigerant every other summer.

Post by **Ben850** » 15 Jun 2014, 23:40

My drier canister blew out the bottom from rust on the '96 Wagon, but I was charging it last year.

It was getting cold at the time, so I knew the compressor was working. Different story, but some of the other issues will be the same.

Post by **kallekula** » 16 Jun 2014, 18:36

have the same problem on my car. the clutch gap is way too big. a friend of mine told me to run a new wire from the battery and put a relay before the on/off cable on the compressor. The stronger current will make the clutch holdup without slipping. Havent tried it yet so I dont know if it works but it might be worth a try.

Post by **jreed** » 16 Jun 2014, 18:54

That's a new solution as far as I've heard. Most people have either added the shims in situ or else disassembled the AC compressor clutch and added shims the "official" way. If you do the electrical mod, let us know if it works.

Post by **abscate** » 17 Jun 2014, 03:41

jreed wrote:That's a new solution as far as I've heard. Most people have either added the shims in situ or else disassembled the AC compressor clutch and added shims the "official" way. If you do the electrical mod, let us know if it works.

This will only work if the resistance of the current wiring is significant compared to the resistance of the magnetic coil of the AC compressor clutch. I would measure this first (battery disconnected) because I think you will find this is not the case.