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System repaired, no improvement

bergtho on Sun August 26, 2007 12:40 PM User is offlineView users profile

Year: 92
Make: VW
Model: Golf
Engine Size: 1.8L
Refrigerant Type: R134A
Ambient Temp: 80
Pressure Low: 0
Pressure High: 120
Country of Origin: United States

History: Original compressor seized up, replaced with rebuilt unit (Sanden SD-508). Also replaced receiver/dryer and expansion valve.

Manufacturer sticker lists system capacity for R12: 40 oz.+/- 3 oz. Installed 36 oz. of R134A

Cooling capacity now: None

If the engine RPM are raised to 2000RPM low pressure moves to 10 inches of vacuum, high pressure moves to 125.

This was supposed to be a straghtforward install, but we're not getting any cooling at all and I don't know why.

NickD on Sun August 26, 2007 1:16 PM User is offline

Seized compressor is the worst case scenario in AC systems, a catastrophic event if you may. What about super flushing out the condenser? Or better yet, replacing it? Your expansion valve screen has got to be plugged up with those kinds of pressure readings, that debris that plugged it up was never removed first. I think, but you know.

JJM on Sun August 26, 2007 1:46 PM User is offline

I agree with Nick - this is likely a repeat case of repeat contamination, causing the TXV to fail. The repeat contamination could also be from the rebuilt compressor if it's a chain store reman and not one from www.ACKits.com. A lot of chain stores compressors are paint, pack 'n ship jobs.

You could also have moisture in the system if it was left open after the failure, causing the freezing at the TXV. Throw a hot damp rag over the TXV body. If the pressures rise and cooling resumes, the system wasn't vacuumed down properly.

The system needs to be flushed thoroughly - except lines with filters and mufflers - and perhaps the condenser replaced. The addition of an Universal In-Line Filter like the one pictured below would be a good idea:



You'll also need to replace the TXV and receiver dryer again, along with any O-rings. Be sure to add back the correct amount and type of oil.

Joe

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




bergtho on Sun August 26, 2007 2:30 PM User is offlineView users profile

We used a Mastercool flush container, AC flush solvent and shop air to flush the condensor, hoses, and evaporator. This did result in some black colored liquid coming out of these items. I'm pretty sure we got most the moisture out, we vacuumed it down for about 3 hours. The compressor was a rebuild from chain, I'm not sure which one. It seemed like a good deal at the time, not so much now. I do appreciate the input.

Where in the system would the in-line filter be placed? Just before the expansion valve?

bohica2xo on Sun August 26, 2007 5:01 PM User is offline

The blockage could be in either the TXV, or the receiver/dryer. With a low side in vacuum, the blockage is severe.

Check the refrigerant path from the condensor discharge. The place where it turns cold is the blockage.

The filter that is pictured should be placed in the liquid line, where it is easy to service, and before the TXV.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

NickD on Mon August 27, 2007 5:59 AM User is offline

Was the receiver R-134a compatible? Over the years, AC has changed simply from changing components to reading the very small fine print.

HECAT on Mon August 27, 2007 12:28 PM User is offline

Did you use an evaporative flush? Did you blow until the component was dry?

The fact that the compressor seized (overheated, burnt oils, metal debris) makes this one of the most severe failures to clean and recover a condenser from.

In my opinion, the flush gun you are using is very limited, especially if still using the OSHA regulated (30 psi) blow gun.

It is also my opinion, that after such a failure, you won't have much of a chance to properly clean the condenser with such a limited tool, and it should be replaced.



-------------------------



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

FLUSHING TECHNICAL PAPER vs2.pdf 

bergtho on Mon August 27, 2007 11:23 PM User is offlineView users profile

I did check on the receiver/drier. It is labeled R134a/R12, made in Brazil. It also has a date code of 09/02, sounds like it may have been on the shelf for a while.

I also checked on the expansion valve. It has R 134a listed on the valve along with the part number and was made in France. The expansion valve on this car has a small insulating foam piece around the outside of the valve. The factory catch for the foam rusted off so I zip tied the foam back into place.

For the flush I used an A/C flush solvent from FJC, I'm not sure if it was evaporative. Side note, I did spill some while filling the flush gun and it didn't all seem evaporate. For flushing we used a Mastercool 1 quart container that is pressurized from shop air. After this we put the shop air (rubber nozzle) on one side of the component and fed in air until the flush fluid seemed to stop coming out.

I did order the in-line filter from ackits and will be putting that in before the system in. In this car it looks like it will fit best on the line between the condensor and the expansion valve. I'll update, hopefully with good news.

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