non MB A/C question
 

Sorry for a "foreign" car question, but I figure someone might know, and I've come to trust yall.
My wife's A/C on her 94 Chevy Cavalier (R134a) just died yesterday. The night before it worked fine. The past few months, something has been jingling/squeeking in the vicinity of the compressor. NOw, the clutch does not engage (I've not tried jumping it yet). ANy ideas?

If its any consolation, this car is such a piece of #@@%$# that its out of hear come the first good deal on an SD I can find!!
THank you,
Paul

jump the low pressure switch and see if the compressor starts. If so I would say low freon. If not then a bad clutch.

Seems like a acute heart failure- Thats the term I use for sudden compressor death. Its sounds like it was already failing for a while but the symptoms just became noticeable during the last days.
Are you sure there is enough freon in the system, because low pressure on freon will not engage the compressor. try putting half can of r134 to see if engages if not I think its the first senario.

For your sake I hope its second senario.

MVK

The first and logical step is what Rebootit said.

Paul:

the pressure switch is on the accumulator (big aluminum can in the low pressure side) -- probably over on the passenger side, but I'm not sure. Unplug the wires and jump the connector with a paperclip or something. If it runs, most likely is low on freon, expecially if it has been cycling excessively and not cooling well. If it cools well, you can replace the switch by simply unscrewing it and screwing another in -- there is a built in Shraeder valve.

Otherwise, check the wiring on the compressor -- if the ground for the clutch is bad you may no longer have a connection and the compressor won't run.

Squeals can be from a loose belt (you have a serpentine, right?), or from a worn-out clutch friction plate. Jingling could indicate a worn out of damaged clutch, in which case it simply failed and won't engage.

I wouldn't try to put any freon in without putting a gauge set on to see what is in there -- fully charged it approaching the limit of what I consider safe for freon cans with the compressor off.

You can directly jump the compressor by disconnecting the clutch lead somewhere and jumping to the positive battery post -- if the compressor runs, and it cools, find the bad connection (probably pressure switch). If it runs and doesn't cool, you are low on freon and need to find the leak and fix it before charging. Most likely leakage points are the o-rings in the line connections and front seal on the compressor.

You have a cylcling clutch orifice tube system -- the pressure switch on the accumulator cycles the compressor to maintain a certain pressure/temperature at the evaporator. There is no expansion valve, just a fixed orifice tube in the high pressure line going to the evaporator.

Peter

I'm not sure with the newer GM's but the older GM's had a fusable link (actually it was a fuse) inline with the compressor which would fail if draw on compressor ( such as low coolant) was too high. Soooo just adding coolant may not be enough. The fact that it happened overnight so to speak would make me think there may be a fuse problem in this solution also. If we put a new fuse in and it kept blowing then we knew the coolant was low ( sometimes we just changed the fuse and all was ok). This may help...I hope it does.

Icesailor

82 300D T
66 TR4A IRS
66 TR4A Solid axel

Thanks guys!
I'll check everything tonight and get back to you with the results. By the way: two leads to the compressor. 1 black, one green.
-/+ or both +??

Paul:

One may be a ground. Easy to check with a volt/ohm meter.

Peter

We were all wrong! I started looking for the pressure sensor, couldnt find it, so moved on to try to put another can of 134 in it. After a little went in, I noticed a high pitched hissing. Seems my problem is a leak in the condensor. (which i do believe was the easiest part to remove on the entire car!) So, I'll see if that is fixable or if I can find a new one. then I guess I'll need oil, 134 and guages. Any idea how much should go in?
thanks again for your help,

with a leak big enough to see or hear you should also replace the drier and while at it you may want to replace the expansion valve if it is easy to get to. Most newer cars it is on the firewall and easy. Then you will want to add 8oz of oil, pull a good vacuum, and recharge to whatever the specs for your car are. Should be on a sticker or plate in the engine compartment.

If you put everything in there by yourself and then take it for charging, it will be cheaper.
Here in NYC it costs about 135 to deep vacuum and recharge the 134 system.

MVK

If you call around the rental places you can rent a pump and gauges for under $40.00. It's what I do although as much A/C work I should just buy the pump:D
I had to replace the expansion valve on the 64 t-bird and man what a royal PIA. It is located under the dash above the steering. Covered with several inches of black tar looking stuff, and has enough space to get one hand up there. I will never complain about how MB built A/C units again. I still have about 40 dash pieces to get back together and many vacuum lines to connect.

WallKnight, How do you figure Rebootit was wrong on the first post after you asked the question. ? He was right on... it was up to you to find out WHY it was low on freon..... and you did.... :cool:

Lethermang, you are right. Rebootit, you were too. Sorry for letting this run so far off topic.
The condensor is getting fixed now, then I'll charge it up, then she's getting a "For Sale" sign while i search for her SD replacement!
Thanks for all your help!

Lock away TXBill!!