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Odd Compressor Noise

Inliner on Wed September 05, 2007 10:33 PM User is offline

Year: 1995
Make: Ford
Model: Probe
Engine Size: 2.0L
Refrigerant Type: R134a
Ambient Temp: 90
Pressure Low: 35
Pressure High: 240
Country of Origin: United States

I have a '95 Ford Probe with what I believe to be a Matsushita - Panasonic compressor. I replaced the compressor when my old unit began making a loud noise from idle to ~ 1200 rpms. The best way I can describe this type of noise is a continuous and rapid ratcheting noise. Like if you hold a socket in your hand with a rathcet attached and let it spin around in reverse.

Anyhow, a replaced it with a rebuilt unit that I got from a guy in FL off ebay. I flushed the system as best as I could, replaced the accumulator, orifice, added 4 oz of PAG 46, and then vacuumed it for 30 minutes. I did not notice anything odd inside the system. The orifice was still in decent shape. There were only a few teeny-tiny metal pieces caught in the screen. For possibly having 12 years of service I found this acceptable no? Well, my new compressor began making the same noise. Like I said, it only makes the noise at low rpms. I'm getting around 35 on the low, and 240 on the high in 90* weather while idling. It climbs to ~300 on the high and falls to ~25 on the low around 2500 rpms. The vents are blowing nice and cold, and they did so before replacing the compressor also.

This compressor has a some type of solenoid or switch on the body of the compressor, and then a seperate wire for the clutch. What is this extra switch? There is only 1 wire where the compressor harness actually plugs into the car's wiring harness. I'm thinking that this may be the cause of the noise. Maybe there isn't a sufficient ground? Any other ideas?

Thanks for reading,
John


Edited: Wed September 05, 2007 at 10:49 PM by Inliner

TRB on Wed September 05, 2007 11:45 PM User is offlineView users profile

Have you checked your belt tensioner? Have you check your belt to see if it is worn?

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Inliner on Thu September 06, 2007 11:21 AM User is offline

The belt has no tensioner (manual adjustment from P/S pump) and the belt looks decent & I know it's tight. I will go ahead and change it though.

Inliner on Fri September 14, 2007 9:14 AM User is offline

I've now changed the belt, and added a nice fat 8ga ground wire to the chassis from the compressor mounting bracket. No change in noise.

A couple of people on the Probe forums are telling me to add more freon. FWIW, this is a common problem on these cars. The guys on the Probe forum call it the "Bug Zapper" noise. Unfortunately, the only solution they offer is to have someone replace the compressor.

Over 2,000 rpms, my high side pressure passes 300 psi, while the low hangs around ~30 psi. Given these pressures, would I be safe to try and shoot another 2-3 oz in there to see if there is any change in the noise? IIRC, ~15 oz got me where I'm at now.



Edited: Fri September 14, 2007 at 9:16 AM by Inliner

2POINTautO on Fri September 14, 2007 9:54 AM User is offlineView users profile

300 PSI says you are already overserviced, bug zapper huh, if this was a Honda it would make a loud noise similar to a card clicking your bike spokes like when you was a kid, bug zapper, I like that one, it is probably a broken reed valve inside???????

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Give all the dirty details
and dont forget the LO & HI pressures
Year, Make & Model would be nice too

iceman2555 on Fri September 14, 2007 11:30 AM User is offlineView users profile

Since the noise issue is the same as the reason for the replacement of the original compressor.....it is quite possible that the compressor is the root cause...however, first insure that all belts...other rotating accessories are not producing the noise...if this has been done and you are satisfied that the compressor is the root cause.....
It was stated that the orifice was not 'in decent shape' with small evidence of debris.....first this means nothing at all. In the past with large tube condensers...the orifice was the primary filter for the ac system. However, with the introduction of the more efficient condensers...the condenser in many instances became the primary filter. The condenser can be severely restricted and this would not be indicated by debris on the orifice filter screen. Additionally a restricted condenser MAY OR MAY NOT be indicated by a excessive high side pressure reading. Much depends on the location of the high side access port.
The compressor used on this vehicle is a rotary vane compressor. It is possible the noise issue originates in the vanes of this compressor. Since no statement was made about excessive gauge reading variations (needle bouncing), a bad reed valve is not suspected.
Also, no mention of how much lubricant was placed in the compressors.....excessive amounts may result in damage to the vanes...as well as insufficient lubricant. Insufficient lubrication could also result in a restriction in the condenser...orifice tube...etc...and any point where the flow of refrigerant becomes restricted...the flow of lubricant deminishes also. Lack of initially recharge may also contribute to this problem.
First, the system should be serviced to insure that it is completely recharged. A temperature drop test on the condenser would indicate if the condenser is restricted.
Also, what type of flush was used.....some of these flush chemicals are almost impossible to remove from the system, and residuals may result in deterioration of lubricants.
My specs state a lubricant recharge of 6.75oz of lubricant....from the post...the system is under lubricated.....combine with other possible restrictions....hence..the noise issue....bearings.....vanes.....the compressor has failed once more.
A 'rebuilt' unit does not indicate a truly remanufactured unit. It is known of many 'rebuilders' that will take the best parts of several cores...a can of black spray paint...and magically a 'rebuilt' compressor is born. A true remanufacturer....the remanufacturing steps are much more detailed and many new parts are installed.
Where to go.....sorry to say back to the basics....if the noise is truly from the compressor.....it is more than likely.....how to say.....oh well....finished. This repair, to do properly, may require a replacement compressor...new condenser....flush the evap...new orifice tube or line....accumulator...correct amount of lubricant...correct type...PAG 100....and of course..and most important a properly recharged system.
On the other hand...if...since the components to necessitate the repair almost require a total system replacement....if it is possible to live with the noise....and the system cools....keep it running till it fails once more and then complete the repair.


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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

iceman2555 on Fri September 14, 2007 11:38 AM User is offlineView users profile


Just a glimpse of the internals.....best guess for the noise....either the vane tips...or more likely....the roller bearings.

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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

Inliner on Fri September 14, 2007 12:13 PM User is offline

Iceman,

Thanks for the reply. May I ask where you got your specifications? I used PAG 46 oil - about 4 oz. Of it. Since I have the old compressor just sitting here, I'm temped to open it up to maybe try and find the source of the noise. There is an audible click as I spin it by hand.

The condenser surely has me questioning it now. The high side pressure climbs with rpm like I've never seen before. From 240 psi @ idle to over 300 psi before 2000 rpms. It is the parallel flow type, and almost impossible to flush on the car of course. It has quite a bit of fin damage to it anyhow.

You raise a good point about the rebuilt vs reman units. This one came off e-bay for about $150. When I see that Ford wants over $900 for a new unit, there may be a bit more value in theirs. $900 for an A/C compressor.... That's aprox 3 times what I paid for the whole car. Oh, did I mention I work for a Ford dealer? Rediculous.

iceman2555 on Fri September 14, 2007 1:40 PM User is offlineView users profile

The lube type was entered incorrectly....these eyes are sure getting a bit old for sure....should be PAG 46.....but the quantity should be correct.
Why not tear the old compressor apart...do a bit on inspection....see where the possible source is....check the bearings for possible spalding...metal break down due to lack of lube.
The 'clink' sound could be the vanes as they move against the internal chambers of the compressor.....but..hey, what the heck...open the thing up and check it out....
If the repair does include a replacement compressor....check various sources....site sponsor would be a good start...may just find a well made remanufactured unit that works....new are expensive...but the dealer....hey...it is a great way to make some extra cash.
Good luck.

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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

2POINTautO on Sat September 15, 2007 12:28 AM User is offlineView users profile

Lots of fin damage can effect air flow and it could be the cause of your overpressurizing. As for flushing the condensor, I cannot remember the technical name but if the flow is like a radiator then it cannot be flushed, that is to say if there are many parallel tubes for freon flow like a radiator has many parallel tubes so water flow through it simutaneously, your flush will just take the path of least resistance and not flush out much debris or not budge a clog. If this is not a one long tube going back and forth throughout the condensor (again, cant remember the two types) then you may want to look at changing it.

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Give all the dirty details
and dont forget the LO & HI pressures
Year, Make & Model would be nice too

Chick on Sat September 15, 2007 5:07 AM User is offlineView users profile

You are say ing the word in your description..
parallel flow condenser* &
Tube and fin*, and the sepentine
Below pic borrowed from AcKits.com web site on universal parrallel flow condenser page,..


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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

Edited: Sat September 15, 2007 at 5:16 AM by Chick

2POINTautO on Sat September 15, 2007 8:51 AM User is offlineView users profile

Yes, the one on the right does not flush very well but plenty of pressure comes out the other end while doing the flush and it looks like it is flushing just fine, but it is not, have seen some of these cut open and a garden hose attached, the restrictions were very noticable due to the height of the water spuirting out the cut section, different heights, just like the water fountain at the mall.

Sometimes an OEM parallel flow is replaced with a cheap type like on the left or a cheap parallel flow with less number of tubes and the cheap condensor is just not capable of cooling very well adversly affecting performance, there is another thread going on right now that I believe is having this very problem as we speak.

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Give all the dirty details
and dont forget the LO & HI pressures
Year, Make & Model would be nice too

HECAT on Mon September 17, 2007 1:58 PM User is offline

2point,

Welcome to the new guy. (Sorry to others for the repeat)

As my specialty is Heat Exchanger Cleaning, I disagree with your statement "cannot be flushed". However I do agree with your comments about "cheap condensers". We have had customers report back to us that our flushing equipment helped them identify defective flow issues with new OEM condensers. Cheap is Cheap no matter the label.

Most "cannot be flushed" statements stem from the fact that these Parallel Flow Condensers (PFC) are difficult to clean, not impossible to clean. The "path of least resistance" rule applies to a constant linear flow and can be overcome with simple physics principles such as velocity and or agitation (pressure pulsing). "Black Death" phobias also perpetuate "cannot be flushed" and it is true that hard carbonized oils will not be removed with traditional A/C flushing chemicals.

Without professional flushing equipment, the understanding of the internal flow paths, and the understanding of the failures and debris loads; PFC's will not be successfully flushed with the common DIY tools such as the little 1 qt flush guns or aerosol products and therefore, the most common recommendation to a DIY technician is that it should be replaced.

Even with specialty A/C shops that have professional flushing equipment, in the cases of destructive compressor failure; it is common for many a shop to replace a PFC to eliminate any question or doubt about the condensers cleanliness or performance. As long as the components remain inexpensive and reasonably easy to change, this is just a safe, smart, and practical business practice.

Some vehicles already have, and the OEM's tell us that this will become more common; a modular one piece cooling assembly (radiator, oil and or trans cooler, A/C condenser, and electronics cooling). Because of the expense of such a components replacement; we are testing and providing answers as some OEM engineers already see that effective PFC flushing will be more in demand.

We have been supplied many complete systems from OEM's that have suffered catastrophic compressor failures, and we have successfully flushed the heat exchangers. Some of the PFC's have had the inlet completely blocked (packed) with metal debris, it can be done.

We do advocate methods to test for cleanliness before reusing any heat exchanger, and do not claim that just using our equipment guarantees a clean component; for there are way too many variables to be evaluated and considered in each failure. Professional flushing equipment is no different a tool than a screwdriver; in competent hands it is amazing what can be done with such a tool, in the wrong hands you can hurt yourself or do more damage than good.


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FLUSHING TECHNICAL PAPER vs2.pdf 

2POINTautO on Sun September 23, 2007 2:25 AM User is offlineView users profile

Thanks for the professional guidance and theory of operation and I understand your concern and need for professional cleaning but almost no one in the forums is looking for this other than for what you just posted, a very clear and concise guide to help decide, Do I flush my own PFC or go out and buy a new OEM or aftermarket PFC. I will concede that if the DIYer has the extra bucks for a professional flush and not enough money for a new OEM PFC, then even I will send them to you. I do not condone aftermarket condensors unless they look very similar to the original, that goes for evaps also, as you know, all heat exchangers are not alike.

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Give all the dirty details
and dont forget the LO & HI pressures
Year, Make & Model would be nice too

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