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climate control

I'm having some trouble with the electronic climate control in my car. Whenever it's on, every 8 seconds or so there's a high squeaking sound coming from under the hood for a second or two. When the squeaking stops, the engine stalls for a second (and sometimes quits when it's in N or P) and after that the engine recovers and everything's back to normal for 5-6 seconds.
The blower works fine so I guess it's the A/C that's causing the problem. The A/C hasn't worked since I got the car (i.e. no cold air coming out), but the stalling and squeaking sound were never there until recently. Before having the A/C checked out I'd like to know if something else in the engine could be damaged with the sound and stalling and all?

climate control

Reply #1 –
could be a locked up compressor.
louie  :birdsmily:
[SIGPIC][/SIGPIC]       
My famous last words:
It seemed like a good idea at the time.        88TC R.I.P.      88 Sport build in progress

climate control

Reply #2 –
Would a revision of the compressor solve that? I've looked around but compressors that fit my car ('88 Tbird 5.0) are hard to find, so I'm thinking about having it revised and retrofitted

climate control

Reply #3 –
I would guess your compressor is locked up.

To test, open your hood and observe the compressor when the clutch engages. If the engine begins to hem and haw when the clutch is engaged, you can be pretty sure you have a bad compressor.

The fix is to replace your compressor. A retrofit (revision) would also be in order.

climate control

Reply #4 –
or,, if you recently had the system charged,, and the aholes did not purge in some peg or pag oil,,,,,,,,,, they helped the compressor to an early grave.

9 out of 10 times,, this is the reason for compressor issues.  A good AC man will pull vac and see if it holds,, make any repairs.,, pull vac again ,, purge oil while under vac or add it with they system open,,, then add refrigerant and test.

just becauee it boggs the engine down,, does not mean the compressor is shot,, perhaps there is TOOOOOOOO MUCH refirgerant added.  If you have too much, this is way worse than not enough at all.  You can lock up a compressor quicker than you can say 10-4 good buddy with too much r12/r134/F type refrigerant. 

Happens all the time.  A mechanic will first relieve presure off the compressor (hold the needle in) and see if the symptoms go away.  If so,,,, like magic you just found your problem.

if your compressor were locked up,, you'd know it cause youd be looking for your belt.  If it were on the verge of locking up,, you'll be waiting for the belto to throw any day now.  Your symptoms sound more like an overcharged system.

i know you said you have no cool air,, but you didnt say if it has presure.  obviously the clutch engages if you do what jeremy said ,,so the circuit is likely working if the clutch grabs,, just not circulating.

climate control

Reply #5 –
An overcharged/overoiled system won't load the compressor to such a degree right off the bat. Even if it was overcharged, the blowoff valve would go off at ~450 psi.

Regardless, if you want to fix the system yourself, the first thing you need is a set of manifold gauges. Then you can properly determine what is wrong, without guessing (like jcassity and I)

climate control

Reply #6 –
I just let the engine run with the hood open. I could see the clutch engage, run for a second (or two) but then stop running. This pattern repeats every 6 seconds or so. I put my hand on a tube left of the expansion valve after the engine had been running for a while and it was pretty cold. I then checked the blower inside the car, but as before the air coming out of it was not cooled at all.
I haven't had it charged recently, and the guy who had the car before me said the a/c never worked at all while he owned it. So I know for sure it hasn't worked for nearly a year now. Given the state of the car when I got it, it wouldn't surprise me if it hasn't been charged for a little longer than that.
I know, I should just head over to the nearest a/c service shop, but before I start spending $$$ I'd like to kind of figure out what I'm up to.
I wonder why the clutch engages but then stops working. Any ideas why that is?

climate control

Reply #7 –
The fast clutch engagement/disengagement is a sign of a low charge. The cold temperature after the orifice tube plays into this diagnosis.

In my opinion, without proper tools...take the car to a qualified A/C center (and I don't mean Jiffy Lube or the like).

You most likely have a low charge coupled with a dying compressor. But, since oil isn't distributed properly in a system with a low charge, it might run ok when you get the right amount of refrigerant in it. Maybe you have a loose belt...

Can you tell if the engine is loaded down the instant the clutch engages?

climate control

Reply #8 –
Quote
Can you tell if the engine is loaded down the instant the clutch engages?

I'm sorry, English isn't my native language, but if a 'loaded down' engine means one that's barely hanging on, that sounds about right. To be honest, I was shocked to see the belt almost come to a complete stop (well, kind of). That probably explains why it sometimes quits when it's in P or N. So I guess my a/c has trouble telling the engine to put in some extra power when it engages?
Or do you mean something completely different?

climate control

Reply #9 –
The most likely option is that your compressor is almost seizing up and is using much more power to turn than normal.

climate control

Reply #10 –
Quote from: JeremyB;161474
The most likely option is that your compressor is almost seizing up and is using much more power to turn than normal.

I wouldn't go quite that far... Guessing the car probably has other problems such as a dirty IAB(Idle Air Bypass)that is causing idle issues... At 20 years and usually neglected, there can be all types small troubles... 

When was the last time any of you bought a 20+ year old automobile that did not have multiple problems???

As suggested take it to a A/C shop and have them check it out... This type service is not for the novice...

climate control

Reply #11 –
But he'll be happy if his $1000 compressor replacement comes down to a $200 IAC cleaning and recharge. :D

climate control

Reply #12 –
the way you have more clearly described the problem tells me the clutch and all related circuits are working.

the timing of how long the clutch stays on and how long it stays off tells me its likely low on r12 or r134.

the noise you hear is wear and tear on the actual clutch assembly.  They are replaceable and you can do it yourself.
The clutch is also widely available at many stores so check around.

put a thermometer in your car towards the back seat area and take a reading.  Next place it up in the vent.  this should tell you if there is a minor amount of cooler air coming in that you dont really notice by comparing the two readings.  this also tells you more information such as you might be low on refrigerant.

a good charged system will provide about 52-55 deg F of cool air.


Check along your lines where they come together at fittings.  If there is grease build up near any fitting,, there is a leak.  For some reason, grease likes to collect along leaky refrigerant line fittings.

i think your looking at a clutch to replace and a full system vac test and recharge.  If your in a hot area, i would suggest it.

BTW,, your doing well working with a bunch of people not speaking your native tongue.:D

climate control

Reply #13 –
thanks :)

I think I'm gonna have to fix it no matter what, because with the climate control turned off, the blower won't work which would leave me without hot air in the wintertime, and it's nice to have some airflow inside the car while driving around in the other seasons, as well as some cooled air in summers.

I'm trying to figure out what to tell the a/c service center: should I tell them to just test the a/c for leaks and refill it (with R416 as R12 is hard to get nowadays), and take my chances with the compressor and clutch? Or should I get a new compressor + clutch no matter what? What would you guys do?

climate control

Reply #14 –
If you are only worried about the blower for the heater, just unplug the connector for the compressor or the pressure switch plug on the acspoogeulator... Either will stop the compressor cycling and the heater will work fine...