2003 Mitsubishi Galant A/C Compressor Clutch

Tiny
DOUGHTHEDJ
  • MEMBER
  • 2003 MITSUBISHI GALANT
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 90,000 MILES
About a year and a half ago my car was in a 30 mph front end collision. I was hit on the corner of the passenger front quarter panel and the hood of the vehicle. The repairs were made by a less than reputable shop that was actually recommended by my insurance company.

About 6 months after the accident my ac went out. I took the car to my regular and very trustworthy mechanic who informs me the repair shop did not replace my compressor, rather they jb welded a valve back on and the weld was no longer holding and I needed a new one.

the weather got cooler and I put it off until it started getting hot again, I am in texas. A couple months ago I purchased a refurbished compressor off ebay and a new dryer at my local auto parts store and had my mechanic put them in. I am not sure about the order of steps here, but he flushed the system, installed the parts, put it under vacuum for a couple hours, and the rebuilt compressor seemed fine.

10 days later, while going down the highway, I heard aloud skreeching sound, my ac light starts blinking and the air starts blowing hot. Once I stopped I turned the car off and then started it again, the ac lasted for 2 minuted just sitting in the driveway, then I got the same noise and the ac goes out. What was happening is the clutch on the ac compressor stopped spinning, the noise was the belt continuing to spin and then the compressor would just shut off.

So I get a brand new aftermarket compressor and not wanting to take any chances this time, we replaced everything but the lines. We replaced the compressor, dryer, expansion valve (yes, you do have to take the dash OUT), condenser, and evaporator. This pos has a brand new ac system in it.

now I am having the same problem with the new compressor. Worked fine for 3 or 4 days and now after about 20 seconds I get the skreech sound and the compressor shuts off. The pressure on the low side of the system shoots up about 10-15 psi as this happens. Its like the clutch is only halfway disengaging or just spinning too slow.

the serpentine belt is new also. There are no leaks or restrictions in the system. The oil still comes out clean so there does appear to be any debris in the system either. Anyone have a suggestion as to what we should look at next?
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Thursday, July 23rd, 2009 AT 5:47 PM

10 Replies

Tiny
BUDDYCRAIGG
  • EXPERT
What are the pressures at when it's working and when it's screeching?

I'm wondering if it's building too much pressure and a cut out switch or cycling switch is bad.

Oh, and PS, would you use the enter key to separate your sentences. It was kind of hard to read your story.
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Thursday, July 23rd, 2009 AT 7:15 PM
Tiny
DOUGHTHEDJ
  • MEMBER
The pressure normally is at 35, which is a little low. There are 2 cans of coolant in it instead of 2.5 or 2.75. The pressure goes up 10 - 15 psi when the screeching happens.

My mechanic was going to take the switches out of my original compressor and put them in the new one. One of the switches is a high pressure switch.

Sorry about the text. I didnt realize it looked like a big block of text but it sure did.
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Thursday, July 23rd, 2009 AT 8:34 PM
Tiny
BUDDYCRAIGG
  • EXPERT
Dont worry about the text, it was your first time here.

I'm wanting to know what the low and high pressure reading are when the compressor is working and when the belt starts slipping.

Most compressors will lock up when the high side gets to about 450. And if your fan is not coming on, or if the fins on the condenser are clogged up, it doesn't take long for it to get there.
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Thursday, July 23rd, 2009 AT 9:08 PM
Tiny
DOUGHTHEDJ
  • MEMBER
I will get exact numbers from my mechanic and let you know.
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Thursday, July 23rd, 2009 AT 11:56 PM
Tiny
DOUGHTHEDJ
  • MEMBER
Here is the email I got concerning the pressure readings:

40 low side, 210 high side. When the compressor clutch makes the noise the clutch rotation slows down and the low side spikes to 60, the high side drops to 200. As soon as the clutch stops making the noise pressures return to 40 low, 210 high. I have removed shim in the clutch thinking it might be spaced to far apart, does not seem to make a difference. When the car is driven the light on the dash starts flashing when the problem occurs. Cannot get it to do that at idle in the shop though. As you know when the light starts flashing the compressor shut off. I feel the low side goes up because the clutch partially disengages and the system is trying to equalize, which is why the high side drops. The clutch should not be disengaging like it is doing.
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Monday, July 27th, 2009 AT 2:10 AM
Tiny
BUDDYCRAIGG
  • EXPERT
I am going to have to wait until I have access to a different computer this evening before I can respond with any suggestions.

I do not like second guessing other mechanics because he has the upper hand because he is in direct contact with the car and can use all of his senses to diagnose the problem.

Where I can only rely on your words.

If you can answer this, is the screeching the sound of the belt slipping, or is it a scraping sound of the clutch slipping?
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Monday, July 27th, 2009 AT 10:00 AM
Tiny
BUDDYCRAIGG
  • EXPERT
If you could, please answer this, is the screeching the sound of the belt slipping, or is it more a scraping sound of the clutch slipping?
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Monday, July 27th, 2009 AT 7:06 PM
Tiny
DOUGHTHEDJ
  • MEMBER
The screeching seems to be the belt slipping around the clutch that is no longer spinning.
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Tuesday, July 28th, 2009 AT 10:31 AM
Tiny
DOUGHTHEDJ
  • MEMBER
I just spoke with my mechanic and he thinks the screeching is the clutch not fully disengaging.
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Wednesday, July 29th, 2009 AT 6:16 PM
Tiny
BUDDYCRAIGG
  • EXPERT
This is what I would do. But I'm not trying to tell your mechanic how to do his job.

I would use a jumper wire to send battery power directly to the clutch as a test.
Checking to see if the compressor clutch has the ability to stay engaged.

If it can, then I would start checking the pressure switches and relays to make sure they can carry enough amps to engage the clutch.

If the clutch doesn't stay engaged with the jumper wire, then I would suspect the clutch, or possibly a bad ground with the clutch.
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Wednesday, July 29th, 2009 AT 6:26 PM

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