854 96 T5 Auto, approx 150000 miles.

It's been 35-40 degrees celsius here during the last two months. It is absolutely IMPOSSIBLE to survive inside my 850 without decent A/C.

Most of the time the a/c is working fine, decent temps. I purchased a digital thermometer that goes into the air vent to measure the air temp. It's cycling fine.

However, sometimes I am driving down the freeway and the whole car will shake. The engine seems to stall for a couple of seconds and then it recovers. It can happen again in 2 mins or maybe not repeat the prob for 5 days. It does not happen regularly.

Sometimes in stop and go traffic or at a light the engine will suddenly die. The engine starts up fine again. it is dangerous because it can happen at intersections at slow speed or maybe at a railroad crossing.

It only happens with the A/C compressor on. It feels like the compressor locks up temporarily, adding resistance to the engine making it stall.

With the A/C off, the engine does not show this prob. I can floor the engine and it will accelerate fine. Doesn't seem to be a fuel admission problem.

Sounds like the compressor is about to die. I had to reshim it 3 years ago and it makes noise like a can full of marbles.

What do you guys think?

 

i think you are right on track. Start shopping for a compressor. Do it sooner than later, if the lockups launch any debris into the system you be hating life.

 

I'd look at the high pressure switch, it could be failed closed. I'm pretty sure it regulates the pressure in the system and hence temp in the car. If it doesn't open when the pressure builds it will put a big, over pressure load, on the compressor and seals. To me it seems like the compresssor is good because if it weren't the load wouldn't be put on the engine and the seals would be leaking from high side to low side.

BTW I had to replace the compressor on my 96NA last spring. It worked fine until I got on the highway and was turning higher RPM(building big pressures in high ambient temps) and had plenty of airflow over the condenser. all of the sudden no AC (because of the high pressure switch) pull behind a truck reset everything, let the pressure equalize, AC bacK on for a bit. Anyway after putting gauges on and spending lots.... of time thinking about it I went with a new compressor instead of the expansion valve. Now I drive a rolling freezer.

 

Thanks guys for your replies.

A new compressor is $375 at FCP groton. Then another $200 at least to get it to Argentina plus $200 to get it installed. That´s an $800 "just in case" expense.

I am building a new house without a bank loan and I don´t have that kind of cash to spare.

How can I check if the high pressure switch is failed closed? It "only" costs $100 so that would be great news.

Thanks
Axel

 

If your car is like my 96's and 98 V70 it doesn't have a high side service port (01 V70 does)so you can't see the high side pressure with gauges. This makes it tougher to troubleshoot, check the high side pressure and the function of the switch. But after reading your initial post again I remembered that I had that marble sounding thing going on before I replaced my compressor (but no stalling). It really could be a number of things, clogged condenser, clogged dryer, switch, even the compressor???

You might think about this http://www.acsource.com/compressorgasketkits.aspx for a rebuild kit if the compressor is bad. I still have my old compressor and will call these guys to get a rebuild kit just to have a spare.

BTW if you replace/rebuild the compressor I highly recommend a new dryer too, It's not like the car is only a few years old.