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Symptom - or - cause

Chevelle_nut on Tue March 25, 2008 10:29 PM User is offline

Year: 1994
Make: Olds
Model: Cutlass Supreme Conv
Engine Size: 3.1
Refrigerant Type: 134a
Country of Origin: United States

I bought this car 2 years ago for my oldest who was learning to drive at the time. Low mileage 2 owner car, had a couple of small problems - one of which was no a/c. Not a problem for me, I was sure I could fix it. Not wanting any reliability issues I opted for a new replacement compressor kit, came with oil ( PAG 46 ) o-tube accumulator/drier. I bought it off ebay ( I KNOW , I KNOW)- some guy from TX ,anyway he seemed very knowledgeable. This is not a V5, but a visteon replacement unit made to fit V5 applications bought new GM hose assy ( has mufflers ) - wasn't going to push luck on flushing them. I pulled everything out of the vehicle but the evap - and flushed it thoroughly. The old orifice tube didn't have any kind of gunk on it and even the recovered flush didn't look bad. I was happy with it at the time. So I thought I had done the right thing - new orings everywhere, new compressor, new drier, new o-tube, new oil, pulled a nice deep vac on it and charged it up. I did the charge the only way I can - by the temps. It worked superb - for 2 years - pretty much everyday here in SW FL. Last weekend as I was driving the car as I went around a corner the car made a horrific sound. A rapping like a pushrod or connecting rod failure - it went up and down with RPM and not vehicle speed. It happened less than 1/4 mile from home. When I got home I nervously started looking around at source of noise. Really sounded like a pushrod, or collapsed lifter. Then I noticed the compressor was making the sound - turned of A/C no noise. Turn it back on - no noise for a bit then it starts. I haven't taken the pressures because I'm afraid the compressor might be croaked. When I looked at the clutch gap it looked huge - measures .045" using feeler guages. Could this be the source of my noise and it's slipping/rapping when the pressure builds up ? Or is it just junk and needs to be replaced.

Oh yeah I forgot to mention - for like 25$ I could have bought a lifetime warranty I didn't because he did such a good job of selling me - I figured this new unit was going to last forever ... doh.

TRB on Wed March 26, 2008 10:52 AM User is offlineView users profile

Clutch gap issue normally does not create a knocking sound. Might as well adjust it before pulling things a part and checking for debris.


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

GM Tech on Wed March 26, 2008 11:04 AM User is offline

My guess is the compressor is noisy due to lack of proper lubrication due to left-over flushing agent that was not removed from the evaporator- those evaps are multi-pass parallel flows- how can you expect to get a cleansing agent out of them? with out pouring it out? Blowing air through it gets some- but not all. This is why I usually do not flush- I would have considered the original failure mode- which was probably a leak- not a mechanical detructive failure- (you stated the OT was clean- so why flush?) then I would have fixed the leak (most likely the shaft seal) and then recharged and let it go- usually can be done for under $200- those OEM V-5 compressor are mechanically strong- hard to kill- they have a separate oil chamber in the crankcase. I see a lot of returned units that when you pop them open- they reek of turpentine like flushing agent smell- it is tough to lubricate your internal compressor parts with a degreaser agent. Your best bet now is to start over- I would flood the system as is with 2 or 3 times the oil spec- in hopes of diluting any residual flush- then tear it all apart and flush all components except evap- and replace others. I would have stayed with GM V-5 as well.

This is all dependent of course in complete verification that the noise is internal to the compressor- the orifice tube would be a good place to look at first- to see if there is any compressor debris in it.....

The air gap by itself would not cause the rod knock noise- it would be a slipping/hissing sound if being too wide may be an indicator of internal wear- or endplay of the shaft from wear.....

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Chevelle_nut on Wed March 26, 2008 12:54 PM User is offline

Phew, I gotta stop typing that late at night.

To cut through the babble-
Would an excessive amount of clutch gap cause a sound like a collapsed pushrod or a rod knock ?
I did a pressure check this morning

Amb ~80 1" in front of condenser
2K rpm
Cabin fan at 3/4
drivers window open 1"

Low 33 - 36 psi steady slow rise and fall
High ~140 to 205 needle pulses within 5 psi all the way up to 205 when condenser fan kicks in and then high side falls slowly to 140 or so. At the low side ~140 the condenser fan kicks out and the high side pressure rises. The knocking noise starts at about 165 on the way up and continues up to high pressure point and fades out just below 160 on way down. I'm wondering if I'm just getting clutch noise during the heaviest load on it. The AC clutch doesn't cycle on and off just stays running. Other than the noise it seems to be o.k.

I'm reading 46 at vents so it seems to still be cooling well.

Some additional info:
Compressor is a VALEO, VC5 model # 10000426, not a visteon - I guess it's a Chinese knockoff.

Chevelle_nut on Wed March 26, 2008 1:20 PM User is offline

Thanks Tim and Mr GM

Sry I missed the answers guys, I'm going to reset gap and post back..

As for flushing it I was worried about the OE oil and not knowing if anyone had attempted a repair before. The new compressor kit came with 8 oz. CoolPro PAG 46, I thought the old PAG 150 might still be lingering about. so I didn't want any mixes. As for the evaporator - who knows what may have been left behind - I puhed ALOT of solvent in there. I did as best I could to clear it out by pushing compressed air , then a good long blast of nitrogen too. As far as I could see nothing of any concern washed out. I'm sure hoping not to pull it out. I do still have the old V5 sitting on the shelf, if the gap adjust doesn't do the trick I guess I'll try a shaft seal on the old one ?? I'ts been capped and sitting since I pulled it.

TRB on Wed March 26, 2008 1:46 PM User is offlineView users profile

I can't find that Valeo number in any of their listings. Sent an email off to my contact seeing if that is even a Valeo compressor or not. Just curious on my part. I have not herd of Valeo producing China knock offs.


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Edited: Wed March 26, 2008 at 1:46 PM by TRB

Chevelle_nut on Wed March 26, 2008 2:13 PM User is offline

Sometimes a picture is worth a thousand words.

First pic is top area of label has part#

Second picture from under car shows Valeo and "Made in PRC"


TRB on Wed March 26, 2008 2:44 PM User is offlineView users profile

Reply from Valeo.


10000426 was an internal part number for Valeo. The part number you need is 10000436.


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

Chevelle_nut on Wed March 26, 2008 5:22 PM User is offline

So maybe this isn't even a genuine Valeo ?

Maybe I should dust of the old V5. If I do decide to resurect the old compressor what parts should I replace ??

TRB on Wed March 26, 2008 5:29 PM User is offlineView users profile

It's a Valeo compressor from their China plant. It is not a knock off or anything like that.


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

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