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HELP: Gremlins taking my R134

meck1 on Wed April 01, 2009 6:39 AM User is offline

Year: 1994
Make: Ford
Model: Ranger
Engine Size: 2.3L
Refrigerant Type: r134

I've got a crazy one going on with an air conditioner like I've never seen before. I'm hoping someone has experienced something like this and can give me an idea of where to go.

This is on my wife's '94 Ranger. This is the typical Ford accumulator system using R134 refrigerant. It has always been ice cold until a few days ago when she told me it was blowing warm air. When I put the gauges on it, there was no pressure at all. So I pulled all connections apart, cleaned them, and replaced all o-rings. I also replaced the orifice tube while I was at it. I then pulled a vacuum on it for 30-45 minutes, shut it off, and let it set. There was no drop in vacuum reading in four hours. I then filled it with refrigerant and some dye and was getting good cold air (32 degrees).

Twenty four hours later, it was blowing warm air again, and the gauges showed almost no pressure. When I put the vacuum pump on it, it pulled a good vacuum and held it. There is no sign of the dye anywhere and all connections on this system are very visible. Only the evaporator is out-of-sight.

Questions: (1) Where in the world can the refrigerant be going? (2) What kind of leak can there be that will not open and leak under a vacuum but will leak under the pressure of the refrigerant?

If anybody can give me a hint of what to do or check for, I will appreciate it.

Thanks

Chick on Wed April 01, 2009 7:56 AM User is offlineView users profile

Do you have a dye light? if so, I'd pull the front clutch plate off and look for a front seal leak.. An electronic detector can also be used. Also check the condenser for a pin hole, but sounds like a shaft seal to me..Hope this helps..

Also, I'm not sure, but does that truck use the steel accumulator with an insulation wrap on it? If so, that would be my number one place to look, peel the wrap off and look for signs of rust, and pin holes..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

Edited: Wed April 01, 2009 at 8:00 AM by Chick

GM Tech on Wed April 01, 2009 9:08 AM User is offline

Totally agree with Chick-- those steel accumulators will rust through at the bottom--under the foam- must peel all the foam off- and most all the Fords I know used steel ones- the GMs were all aluminum for that very reason....

When you find the leak it will be a "no-doubter" that much refrigerant in 24 hrs will have a lake for a dye spot-- you may do well to pull the evaporator drain tube- look inside it for the dye-- and pray it is not in there.....

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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......

meck1 on Thu April 02, 2009 11:03 AM User is offline

I appreciate your responses. The puzzlers in this situation have been (1) that the system can hold a "perfect" vacuum indefinitely yet there be a major leak somewhere, and (2) that there is no sign of dye anywhere when there should be a bunch someplace. Yes, I have the Ford accumulator covered with foam insulation. I haven't torn the insulation off it but will do so, although it seems a leak, even a pin hole, should show up as a loss of vacuum. I'm leaning toward the compressor seal as the source of the problem but have decided to wait until I can get a detector. I've got one on order now.

Thanks for the time you took to write.

TRB on Thu April 02, 2009 11:37 AM User is offlineView users profile

Put a shower cap over the clutch assembly. Let it sit for a while and then us an electronic leak detector sticking the probe inside the shower cap. There is a large difference between the positive pressure a system can generate compared to a vacuum check. Many times a system will hold under a vacuum only to show signs of a leak once charged.

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

Chick on Thu April 02, 2009 6:04 PM User is offlineView users profile

Remove the foam, check it out..

One of Ford's better ideas...



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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

JJM on Thu April 02, 2009 9:06 PM User is offline

I don't recall if the '94 had a PRV, but if I remember correctly, it's on the compressor hose/manifold assembly - which isn't cheap, assuming it's still available. The valve could be letting go prematurely.

Joe

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



TRB on Thu April 02, 2009 9:29 PM User is offlineView users profile

Quote
Originally posted by: JJM
I don't recall if the '94 had a PRV, but if I remember correctly, it's on the compressor hose/manifold assembly - which isn't cheap, assuming it's still available. The valve could be letting go prematurely.



Joe



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



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

meck1 on Mon April 27, 2009 6:27 AM User is offline

The leak was in the accumulator under the band that is clamped to it and that supports the accumulator. I figure the band must have been tight enough to let me draw a good vacuum without any loss but expanded enough under pressure to let it leak. Regardless, leak is found, part is replaced, problem solved. Thanks for your help.

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