# noisy Car AC compressor



## raymilosh (Jan 12, 2005)

Hi all,
I have a 93 suzuki swift with 265K. Great car. It has needed zero repairs yet, other than maintanance and brakes.
Anyhow, when i turn on the AC (which amazingly still works, too) the compressor makes a loud noise that is hard to describe. the noise is kind of a constant low howl. the noise decreases with time. 
When the AC is off, it makes no noise at all.
The AC doesn't seem to have any other symptoms. It has been making this noise since late last summer. I haven't used the AC all that much, but it has certainly run for a total of 5 or 10 hours in this condition.
Anybody know what makes the noise? What do I need to do to fix it? 
I know little about AC systems, but I understand there is oil mixed in with the coolant in the system...is it possible it needs changing or topping up? 

A reference to how to charge and diagnose and understand AC systems would also be appreciated, as I have a car (88 acura integra) to work on where the compressor turns on, but it doesn't get cool and I'm wanting the see about recharging it.


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## OkieDavid (Jan 15, 2007)

The problem on your Suzuki could be a loose belt. If the sound decreases within seconds or when you throttle up, check the belt tension. The other possibility is a weak fan clutch but I'm discounting it since you say the sound goes away. My suspicion is that if it was low on freon you would feel it at the vent.
As for recharging a system- that one is much more dicey...The first question is "where did the old freon go"? If there is a leak in the system that isn't corrected you are just throwing good money after bad. Second question is SAFETY- Accidentally hook up to the high pressure side and you can blow the can up in your hand. Do you know enouch to trace the lines from the compressor to the dryer (large insulated aluminum cylindrical device just before the lines go through the firewall). If so- look very near it and see if you can locate a fitting that resembles a tire inflation valve. Once located- see if the stem is threaded (like a tire valve) or more like a quick connect fitting similar to air operated hand tools. Not shure when they changed over from threaded fittings and R12 to quick connect fittings and R134... The quick connect fittings are the modern safer ones and the recharge kits you get from the auto center (R134) will only fit on the correct "low pressure" side. Fill/recharge with the engine running and the A/C turned on. To be safe- get the recharge kit that has a gauge on it and be prepared to QUICKLY disconnect it if the gage goes in the red.


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## raymilosh (Jan 12, 2005)

The noise is not a loose belt. I also happened to replace the belt last week and the sound is the same. When I said the noise "goes away", I should have said that it gets less noisy over the course of several minutes, but it is still loud enough that a person standing there would say "What's wrong with your car?"

Regarding the 88 Acura. I know enough about ac systems to trace lines and name all the parts and I understand basically how it all works. I have just never actually messed with them before...like replacing parts, fixing leaks, diagnosing noises and the like. 
I have read the cans and gages at the auto parts store. I get that I need to put on an r12 to r134 adaptor and to watch the gage as i fill it. there are also some cans that contain tracer dyes that will leak out and can be seen by a flourescent light, so the leak can be repaired. there are also some cans of oil and some cans of freon plus oil there. I'm looking for a detailed description of problems and solutions and methods from someone who has had a lot of experience with AC systems and who has written it down and stuck it here on the internet somewhere.


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## OkieDavid (Jan 15, 2007)

Okie Dokie then.... I'm sure someone has probably put that stuff on the internet by now. Back in 1981 when I received my first formal education our A/C refrigeration class was all in textbooks. In all the years since- most of my learning has come from working under the hood. I wish you well in finding what you seek.

As to your other car- with the updated description, I change my diagnosis to a; 1. Bearing failing or 2. Bad compressor clutch.


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## Rocky Fields (Jan 24, 2007)

Hey.

The refrigerant has oil in it for lubricating the compressor. If you're low on refrigerant, it could make noise. Compressor has a clutch on the end, the clutch may be bad. And of course, the compressor itself may be bad. I've seen rebuilts for around a $100 on eBay for some makes.

RF


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## fixer1958 (Dec 12, 2005)

Your compressor is fixing to die. That's a death rattle.
Nothing you stuff in the system is going to heal it.


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## cfabe (Feb 27, 2005)

I agree with fixer1958, the compressor is on its way out and needs to be rebuilt. If I owned that car I'd probably just cut the wires to the a/c clutch so it couldn't be used any more and forget it had AC. But, I don't live in North Carolina, so if you want to fix it it will probably need a new/rebuilt compressor and a evacuate/recharge. A 1993 probably has R134a so at least you won't have to pay for R12.


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## fixer1958 (Dec 12, 2005)

As a rule of thumb, for me anyhow, is they didn't start using R134 till 95'.
Even then the knowhow wasn't there and the condensers are to small. It takes a pretty good compressor to do a retrofit because otherwise it won't hold up to the higher head pressure because of the condenser undersize. Less heat transfer= higher temps/pressure.


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## cfabe (Feb 27, 2005)

Had a 1993 chevy with R134.... guess there were some years where you can't be sure.


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## agmantoo (May 23, 2003)

I was under the impression that the 1994 Buick was the first factory OEM 134R units for GM.


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## cowcreekgeeks (Mar 5, 2009)

It could be the bearing. Our Honda made an awful racket until I replaced that bearing.


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## cfabe (Feb 27, 2005)

Vehicle was a 1993 Chevy Lumina APV. Definately R134a, just verified in a service manual (don't have the car any longer).


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## raymilosh (Jan 12, 2005)

thanks for all the responses. Now i have more questions.
I get that the compressor is probably failing and that even a new compressor may not be good enough if i convert from r12 to r134, because r134 requires more pressure. 

Could rebuilding the compressor mean just replacing the bearing, or is there more to it than that? Is this a bearing that could possibly be replaced without needing to release the refrigerant?


Also, kind of a side question...let's say i have an r12 system that has no longer produces very cold air, can I just put on a r134 adaptor and charge it up, look for leaks nad repair them and that's it, or are there other steps? (Like replacing a filter, or needing to evacuate the system first or do some research to see if the system is even able to run 134 due to the highre pressure requirements)


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## Cannon_Farms (Aug 28, 2008)

Change the filter/dryer bottle(silver bottle ),orifice tube, vacuum down the system to -30 lbs to suck moisture out of the system and check for leaks. if it will hold vacuum for 15 mins then it can be recharged with R134. Unplug the pressure switch and jumper it across (with the engine running) and begin to introduce the coolant. Once you have about one and a half cans in,unplug the jumper and plug the connector bact to the pressure switch. If things are working correctly,the compressor should kick back on.
Check at the vent with the fan on high,using a spike type thermometer,air temperature on a good working system should be aroung 60+ degrees or lower. do not overcharge the system.( most retrofits only use 2/3 of the coolant amount that r12 sytems normally hold.) working pressure on the high side should not exceed 180 psi. low pressure 30 to 40 psi. Now,the downside. R134 looks for ways to escape much harder than R12. Its thinner,sneakier and will leak out in a heartbeat. If you can find someone who can get you some Freeze12 you can put it right in with the old stuff. Good luck. Have fun. Calvin ( survivor of 3 retrofits on personal vehicles. Mechanic for way too long. Brother of a certified 
Goodyear A/C tech)


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