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VW Jetta AC trouble

noresttill on Mon January 19, 2009 11:29 PM User is offline

Year: 2001
Make: VW
Model: Jetta
Engine Size: 2.0L
Refrigerant Type: R134
Country of Origin: United States

Ive posted this on the various car forums I am a member of, but have not yet received information usable to me. im glad this forum is here, seems like a wellspring of knowledge. I on the other hand dont know much about air conditioning, but am good mechanically so hopefully this problem is fixable at home.

about 4 months ago, my Ac stopped blowing cold. It still blowes but only outside air temp

I checked yesterday to see if I had pressure in the system by pressing the valve, a lot of pressure, so dont think its a leak as it would have depressurized (right?)

There is a noise in my accesory belt area, and when the ac button is pushed the engine stumbles whenever the compressor tried to go (every few seconds)

So I figure its the compressor/clutch.

I dont have any ac equipment and would like to do most of the work myself (money is kinda tight).

Here are my questions:

1: Is it possible to get a R134 purge and flush from an ac shop, drive home swap out the compressor, then drive back and get it refilled? or must the compressor be taken off before the flush.

2: Can I do a purge, flush, or refill with products from an auto parts store? Ive seen those canesters of R134 with a gauge, is that enough for a proper refill?

3: I found a salvage compressor with warranty from a well established yard for a great price. Can it just be installed? or do I have to add oil, if so what oil?

I am open to new ideas, and will search this site, but wanted to get this question out first.

Thanks

HECAT on Tue January 20, 2009 10:53 AM User is offline

Just because you have remaining pressure does not rule out a leak. Refrigerant may have leaked causing poor cooling and poor oil migration, which can damage the compressor.

1. Yes a shop could recover the refrigerant, flush the system (if they have equipment), and then vacuum and recharge when you have completed the repairs. The issue would be finding a shop willing to do so.

2. Releasing (purge) to atmosphere is illegal. Pour in and blow out flushing is ineffective, you will need equipment. You may want to read the "Flushing Technical Article" attached to the first post in the "A/C flushing forum" for a better understanding about flushing. The kit you refer to is known as a "death kit" and will usually contain system sealers than can damage the system. I would not consider using this.

3. Used compressors are risky business considering all the sometimes overlooked time and expense required to clean and prepare the system for a replacement compressor. All the potential debris and old oil must be removed so the proper amount of fresh can be installed. The TXV will at least need to be verified as clean and the Dryer will need to be replaced. Many times the condenser is also replaced when an effective flushing solution is not available.

The specification for the amount of refrigerant and the type and amount of refrigerant oil required is usually found on an underhood sticker.

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

FLUSHING TECHNICAL PAPER vs2.pdf 

mk378 on Tue January 20, 2009 5:23 PM User is offline

As HECAT noted, a system with a slow leak will stop cooling LONG before the pressure reaches zero. You get all the cooling action from the last few ounces of refrigerant charge.

Also the compressor cycling on and off rapidly, pulling hard enough to make the belt squeak, could be an overpressure situation because of failure of the condenser fan. If that is the case it might cool when the car is moving (faster than 30 mph) to force air through the condenser, but not when it is sitting still.

You really need a manifold gauge set in order to troubleshoot further.

TRB on Tue January 20, 2009 6:36 PM User is offlineView users profile

Sanden Compressor SD7V16

Variable displacement compressor, proper refrigerant level is a must for starters and control valves are known to fail on these compressors.

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Contact: ACKits.com

noresttill on Wed January 21, 2009 12:10 AM User is offline


thanks for the responses.

HECAT:
So if the compressor is the culprit to solve my problem I must:
1. Find a shop to do this
2. Get my system purged and flushed at said shop
3. Change out my compressor and dryer using this http://www.autoacforum.com/messageview.cfm?catid=20&threadid=12050 to prep compressor
4. Drive back to shop and get system restored.

Did I miss anything?

mk378:
The belt noise is constant with the engine running (sounds like a pully), but also has a stumble whenever the ac is on and the compressor wants to cut in. At any speed the air is not cold. I know that I lack the tools to do this properly, but perhaps to cost of non professional set would be cheaper that going to a shop.

TRB:
Any noise associated with the sanden failures?

Thanks again its pretty hard to find info on auto ac problems. I couldn't even find a troubleshooting flow chart.

N




HECAT on Wed January 21, 2009 6:18 AM User is offline

Quote
Originally posted by: noresttill
thanks for the responses.



HECAT:

So if the compressor is the culprit to solve my problem I must:

1. Find a shop to do this

2. Get my system purged and flushed at said shop

3. Change out my compressor and dryer using this http://www.autoacforum.com/messageview.cfm?catid=20&threadid=12050 to prep compressor

4. Drive back to shop and get system restored.



1, 2, & 4: I answered your questions following your strategy of using a shops services. I am not saying you cannot do this yourself. It will take some learning and an investment in some tooling; but it can be done and you can find all the tooling and assistance here.

3: I am glad to see you found B's post on oil flushing and testing a compressor.

It is hard to find the hard step by step data you seek because too many variables are involved in an A/C failure. Keep reading and asking questions, there is a huge wealth of knowledge here to help.


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

FLUSHING TECHNICAL PAPER vs2.pdf 

Chick on Wed January 21, 2009 7:10 AM User is offlineView users profile

As stated above, you need to find out if you have a leak, or other problems. This could get expensive running back and forth to shops. The first step would be to get pressures, both high and low when the car is cold, and when it’s running, post the pressures, static (car off and motor cooled down) and then while running, along with the ambient temp you take them at. The compressor your car uses is a variable displacement compressor and pressures will tell us a lot. If you want to do your own repairs, you should get a set of gauges, they are cheap enough and will save you from running back and forth to the shop each time you want to check something. Or go to a shop you trust and have them evacuate the system and refill to the proper charge level, adding UV dye (your car probably has it in there already, but be safe and add some)
It will actually be cheaper to buy a few bvasic tools, than to keep going to the shop. Check out Mastercool gauges and tools, and if you get the stater kit, you can do everything even recharging the system.. Do it right and you'll do it once..hope this helps.

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Chick
Email: Chick

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