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lutherfetch on Fri October 02, 2009 10:37 PM User is offline

Year: 1998
Make: GMC
Model: Jimmy S15
Engine Size: 4.3
Refrigerant Type: 134a

Purchased a brand new Sanden compressor from ACKits last summer. Thing is already chirping loudly while engine runs. really annoying. does it with a/c on or off. Makes no difference. Clearly a bad bearing or clutch. Anybody work on these things? Debating putting on a junk yard compressor as I cannot imagine one from the bone yard being much worse. I only have 6000 mi on this compressor... and very little of that was with the a/c running. Would appreciate any help / support for salvaging this expensive unit.


My Ongoing Project...

Edited: Fri October 02, 2009 at 10:43 PM by lutherfetch

newton5 on Fri October 02, 2009 11:29 PM User is offlineView users profile

That sounds like general, worn belt noise or an idler pulley getting sloppy causing belt misalignment. It may "chirp" on the AC compressor pulley if the belt is fed to it at a slight angle.
A failing compressor bearing usually won't "chirp". They will usually whine or growl.
A tight clutch gap "can" chirp, but the clutch gap gets wider from use, not tighter. It would also go away completely with the clutch engaged.
It sounds like you might be blaming the messenger, not the problem

Edited: Fri October 02, 2009 at 11:33 PM by newton5

TRB on Fri October 02, 2009 11:30 PM User is offlineView users profile

Pressure readings would be nice. Those Sandens are solid units so I would try and determine why there was a failure. If it's still under the year warranty we can always send it in and see if supplier will honor a warranty. As for the chirping that could be a clutch gap issue or even a belt related issues. One thing we miss on the forum is the ability to see an item in it's working mode. Any discoloration on the clutch assembly?


When considering your next auto A/C purchase, please consider the site that supports you:

NickD on Sat October 03, 2009 5:44 AM User is offline

CS-130's also chirp when the bearings are going due to the small clearance between the rotor and stator. Also a corroded tensioner causes that, has to be smooth throughout it's range and have around 120 ft lbs of torque, that happens more than once. As can a wobbling idler pulley. Takes an effort to find the source as the metal carries the sound seven times faster than air. Just sayin'.

iceman2555 on Sat October 03, 2009 8:10 AM User is offlineView users profile

Prior to 'blaming' a component TRB said operational pressures would be nice....although if the system was not properly recharged using the correct recharge equipment (calibrated scales and not the scales from the bathroom) they are almost meaningless. The proper/correct recharge rate are the foremost failures for a DIY'er and the primary cause of compressor failures. This is valid for any compressor manufacturer. If sufficient refrigerant is not introduced into the system, lube flow will suffer and then the compressor begins to 'bind' internally and thus the extra drag result is severe clutch wear. Excessive heat produced by a slipping clutch results in pulley bearing failure.
However, considering the age and possible mileage of this vehicle, Chick's response has a great bit of validity. Check all aspects prior to making such assumption.
Good luck!!!

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

Voyager97 on Sat October 03, 2009 1:55 PM User is offlineView users profile

Check the belt first.

My '97 Grand Voyager is notorious for the 'chirp' - generally caused by a mis-aligned belt.
One very simple test is to spray a mist of water on the inside surface of the belt while the engine is running. If the 'chirp' stops briefly then the problem is not mechanical.

Vic @ Pennine AutoChill

Edited: Sat October 03, 2009 at 1:55 PM by Voyager97

mk378 on Sat October 03, 2009 7:18 PM User is offline

Yes if the pulleys are not all in the same plane, you will get wear and noise from the belt. You may need to adjust the compressor mounting position.

The first thing to do though would be to take the belt off and spin each accessory component by hand to see which if any of them are obviously the source of the noise.

Chick on Sat October 03, 2009 8:37 PM User is offlineView users profile

Chirping with or without AC on, is usually the pulley on the tensioner or the idler pulley, I have a 97 (with the seltc compressor) and I have had to change both of those pulleys already.. Wit the belt off, don't just turn them, feel for rough spots or play in them..

Email: Chick


Freedoms just another word for nothing left to lose

lutherfetch on Sat October 03, 2009 9:47 PM User is offline

I have replaced everything looking for the source of the sound... new alternator, tensioner, fan clutch, idler, PS pump, water pump, and 2 belts (just to be sure). I have also scrubbed all the pulleys to make sure there is no schmutz on them. It has always sounded like the a/c... but with it being so new, I assumed it had to be something else. Since I just painstakingly rebuilt this engine 2 years ago and plan on keeping it as my wife's kid hauler, I don't mind putting all the new parts in. As for filling and charging the unit... all my information has come from you on this forum and I have followed it to the letter. Also, I should have noted, when you first start the engine, it is a chirp. After driving for a while, it is a consistend high pitch sound. Turning on and off the a/c makes no difference in sound and so I did not bother taking measurements. It sounds like the bad bearing I once had in an alternator. I will definately go through and make sure everything is on the same plane tomorrow. That may very well be the problem. The problem DID go away for a while after replacing the belts. Also goes away when belt is off (so it is not the eng.) Can put a laser level on it and report back. Will begin with p/s pump pulley as prime suspect. Would be THRILLED if that is the all there is to it! Will look for discoloration... but I have been in there quite a bit and have not seen anything unusual. Also, let me also add I am really impressed by 7 responses in 24 hrs. You guys rock! Thanks again, john

My Ongoing Project...

Edited: Sat October 03, 2009 at 10:45 PM by lutherfetch

HECAT on Sun October 04, 2009 7:55 AM User is offline

The problem DID go away for a while after replacing the belts.

I have an 02 S-10 Blazer that had a constant chirp. Seems the common fix is a new tensioner and belt, so I picked them up and got ready install. Could not find anything wrong with the tensioner after disassembly, so I cleaned lubed and reinstalled it with the new belt; and returned the new tensioner to the parts store. Chirp was gone but returned in a week. Constant belt dressing with different materials would quiet it down, until it returned in almost 1 week every time. I decided that it must have something to do with my selection of a cheap belt, so I purchased a much more expensive name brand belt. Installed the premium belt, tossed the cheaper one in the roadside emergency kit; no more chirp. Just my experience as food for thought. Good luck.


HECAT: You support the Forum when you consider for your a/c parts.


NickD on Sun October 04, 2009 8:28 AM User is offline

Here is the right spot.

Soon after I got my daughter that Ford ZX2, we had that chirping sound with a high pitched whistle like sound that could easily drive you nuts. It was in the PCV system, replaced the PCV valve with a Ford OE unit and cleaned up the rest of the system, but have to tell you, trying to find the cause of that chirping almost drove me nuts. Maybe it did. Never ran into anything like that before. Air flows through the system and with debris, not much of it produced a whistling sound and with a slightly weak spring but perfectly clean PCV, it would pulse producing the chirps. It all seems logical now, but didn't when I started.

Helps to use a stethoscope to help find the source. See they make them now for automotive, still using a piece of heater hose, should update.

Olds442 on Tue October 06, 2009 1:00 AM User is offline

You could try a poor mans stethescope. Put one end of a 1" x 1" piece of wood on each component and the other end to your ear. See if you can detect where the sound is coming from.

JACK ADAMS on Tue October 06, 2009 1:04 PM User is offline

I have a 1995 Chevy S-10 with the 4.3L, as well I had issues with the a/c making noise with the a/c on, found the alternator/power steering bracket loose and cracked. Once that was fixed, I had no more noise. So make sure you have no cracks and all bolts are good and tight as well as the belt is a good one (Dayco or Gates)! Cheap belts tend to stretch more and wear quicker…

lutherfetch on Mon October 19, 2009 11:29 PM User is offline

Hey all,

havent been avoiding replying... had something come up. My wife gave birth to our second child, and then I promptly ruptured another disc in my back. So, the Blazer and A/C has been low priority.

I have tried a mechanics stethoscope. It has been useless in diagnosing. I had REALLY hoped to find a crooked belt. It is straight as an arrow. Uless there is something I can't see, it is not the problem. I am convinced there is a bearing out in the compressor. For what it is worth, it is a DAYCO belt.

I DID give you some misinformation in the diagnosis process. The noise does get much quieter and sometimes goes away completely when the a/c is running. So, I wanted to ask again if anyone replaces the bearings on these units or am I really SOL after only 6000mi on a $300 compressor? Would love to get it fixed if it is at all possible. Will put in a HELP pulley or an old core while having it serviced. Please let me know.


My Ongoing Project...

Edited: Mon October 19, 2009 at 11:32 PM by lutherfetch

TRB on Tue October 20, 2009 12:04 AM User is offlineView users profile

Originally posted by: TRB
If it's still under the year warranty we can always send it in and see if supplier will honor a warranty.

Also what bearing do you think is the issue, internal compressor bearing or the clutch bearing? Still don't see where you have listed the current pressure readings when the system is acting up! What is the invoice number so we can look up what was purchased and when?

When considering your next auto A/C purchase, please consider the site that supports you:

lutherfetch on Tue October 20, 2009 10:31 PM User is offline

It is about 15 mo old... but the Blazer really never goes anywhere as it is my wife's kid hauler. The compressor has about 5800 mi on it. As for what bearing, I couldnt tell you. I have never pulled a compressor apart. I have done a few alternators, but this is a different animal. My best guess is the when the clutch is spinning free is when we have the problem. Hmm. Maybe I can blast that out with some brake cleaner and see what happens.

I will get out my guages and get you some readings tomorrow if it is not raining. Spent 7 hours in the car today driving to Cheyenne to see a neurosurgeon. Will likely be under the knife soon... so if I disappear again... I will be back shortly (hopefully)


My Ongoing Project...

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