Massive freon discharge after engine shutdown...need help!!

[Jbreedon]

This is an ongoing 3 month project that's kicking my butt! I have replaced the compressor (twice), condenser (twice), accumulator (3 times), orifice tube (3 times), manifold hoses, evaporator. Completely disassembled system, flushed everything, changed all o-rings, added 8 oz pag 125 (4 oz compressor, 1 oz condenser, 1 oz, evaporator & 2 oz accumulator). Primed compressor, pulled a vacuum below 30 for an hour & let sit overnight. No leaks. Charged originally with approximately 32 oz of r134.  Everything works great. Reading "2" bd code 028. Blowing 47 degrees on 95 degree day. I've done this 3 times. Each time, 5-10 minutes after engine shutdown, the entire load of freon blows (almost explosive) From the top of the evaporator. The last time (today) I only charged with 24 oz.  I'm at a brick wall. I've researched to no avail. I'm hoping my good friends on the forum might have an idea. I haven't found any restrictions while flushing the system. Orifice tube is clean. Any ideas are most welcome.

Regards,

Jim Breedon

89 Reatta

Sweltering in Jacksonville!

[ski.dive]

At this point, I would take it to an A/C shop.

[Ronnie]

How can you tell it comes from the top of the evaporator with it inside the dash in a box? Does it burst the evaporator?

[Jbreedon]

How can you tell it comes from the top of the evaporator with it inside the dash in a box? Does it burst the evaporator?

 

The evaporator hoses connect on the firewall passenger side.

[Ronnie]

Is freon blowing out of one of the fittings? If so new (or the incorrect) o-rings must be leaking.

[Jbreedon]

I've used new green o-rings each time I've had to open the system. The top of the evaporator has the 2 hard lines going to it with a "hold down clamp" to keep both lines secure. Not sure what the torque value is supposed to be. I've tightened the bolt very snug. Is there special o-rings or washers (similar to the compressor) that should be used? I've only used green o-rings (thickest ones tbat fit).  Would using thd variable orifice tube equalize the system?

The last time I put it together, i drove around for about an hour & everything worked fine. Turned the a/c off & left the car idling for about 30 minutes while I checked for codes (none). Once I turned the engine off, 5 minutes later is when it blew from the top of the evaporator. Hard to tell which line its blowing from since they're so close together. I've assumed it was the high side. 

Thanks for the continued discussion Ronnie.

[Ronnie]

I think the o-ring may be blowing when the engine is off due to the fact that the evaporator is on the suction (low pressure) side of the system. When the system is turned off the pressure equalizes and the pressure goes up. I'm thinking the clamping force on the 0-ring is marginal because the fitting are bottoming out before the 0-ring is compressed properly. That could be due to the 0-ring not being large enough or isn't fitting properly.. I've not changed an evaporator in my Reatta so I'm not sure what the problem might be. Maybe Harry, who knows a lot about the Reatta AC system will chime in and offer you some help.

[Jbreedon]

Thanks Ronnie,  I appreciate all the help I can get at this point. Lord knows I have plenty of O-Ring kits (now)! I'm researching what I can find for illustrated parts breakdowns to see if there's a "special" o-ring" or some type of adapter I may have overlooked on first disassembly.

Best reason in the world I can think of to take DETAILED pictures of all work being done.

 

Thanks again for your help & suggestions.  If I stumble across the fix, I'll certainly share it with the group so no one has to go through this.  I've serviced many a/c systems with my brother over the years. This is a new one for me!

 

Regards,

 

P.S. sorry for the misspellings in the previous post.  I was responding from my phone...phat phingers :exclamation:

[Ronnie]

Perhaps the photos below will help in your search for the proper o-ring. They are taken from the factory parts illustration catalog. Take note that the text says o-ring #3 is "Blue". The part numbers are probably too old but maybe you can cross reference them. Good luck!

[Jbreedon]

Thanks Ronnie. Haven't had any luck cross referencing o ring p/n. I used the thickest o-ring i had that fit the tubes. Still escaping from the evaporator fittings after engine shutdown. I agree the tubes aren't properly seating. According to the drawing, it only uses o rings. All of the o ring kits have black "shims" (very thin flat washers). Wondering if they may be used??? Perhaps a "special" sealing washer similar to the compressor port?

Wanted to fix the a/c for my brother who has been allowing me to use the car for the past year. Guess I'm going to have to admit I'm beat & take it to an a/c shop. I don't think they could do it better than me but I'm sure they have much more experience & knowledge.

Thanks again for all of your help.

Perspiring in Jacksonville

[Ronnie]

I was happy to try to help. Wish we could have solved the problem.

[retired mechanic74]

Thanks Ronnie. Haven't had any luck cross referencing o ring p/n. I used the thickest o-ring i had that fit the tubes. Still escaping from the evaporator fittings after engine shutdown. I agree the tubes aren't properly seating.  According to the drawing, it only uses o rings. All of the o ring kits have black "shims" (very thin flat washers). Wondering if they may be used??? Perhaps a "special" sealing washer similar to the compressor port?

Wanted to fix the a/c for my brother who has been allowing me to use the car for the past year. Guess I'm going to have to admit I'm beat & take it to an a/c shop. I don't think they could do it better than me but I'm sure they have much more experience & knowledge.

Thanks again for all of your help.

Perspiring in Jacksonville

 

...Reading about the problem you have it is obvious your compressor is building up to much pressure and the high pressure switch could be sending the signal, but the programmer is not receiving it and therefore the compressor is not cycling and after 5 to 10 minutes of cool down it allows the system to rupture. Being you live in a hot climate exacerbates the problem. Put the manifold gauges on the system and run the car for 15 minutes and watch the hi side gauge it should stay around 150 P.S.I. low side should read around 29 P.S.I. If the hi side climes up to 250 put a fan in front of the condenser and the pressure should come down if not then I would look for an electrical problem. Hope this helps. (Note) the 150 and the 29 indicate that you have the proper amount of free-on in the system.

[Ronnie]

Please let us know what it takes to resolve this problem. It might help someone with a similar problem down the road....

[retired mechanic74]

Jbreedon could you tell us how you are charging the system? That might give us a clue. Are you using manifold gauges?

[Jbreedon]

I'm adding 2 cans (24 oz.) Through the low side service port on the accumulator. Afterwards I put the gages back on. It appears the high side Schrader valve may be too short as I'm not getting a high side reading at all. ( Reads the same as low side with both connected). That's a fix for tomorrow. I haven't used the manifold gages to add freon. The compressor seems to be working correctly. It's cooling during all a/c modes. Turned off, during idle, it's freewheeling with the clutch stationary. Not receiving any codes during operation. I'm replacing the alternator tomorrow for an unrelated issue. I'll fix the schrader valve & post the readings.

Thanks again for the ideas.

[retired mechanic74]

I'm adding 2 cans (24 oz.) Through the low side service port on the accumulator. Afterwards I put the gages back on.  It appears the high side Schrader valve may be too short as I'm not getting a high side reading at all. ( Reads the same as low side with both connected). That's a fix for tomorrow. I haven't used the manifold gages to add freon.  The compressor seems to be working correctly. It's cooling during all a/c modes. Turned off, during idle, it's freewheeling with the clutch stationary. Not receiving any codes during operation. I'm replacing the alternator tomorrow for an unrelated issue. I'll fix the schrader valve & post the readings.

Thanks again for the ideas.

 

I would suggest that you use the manifold gauges when charging the system, as you are charging watch the gauges and when it shows 50 on the hi side start the engine and run in the free-on until the low side reads 29-30 and the hi side reads 150 stop charging at that point. Two cans may be to much??? I assume you did a retro-fit and are now using 134 Also I read that you put 8 oz's of oil into the system? All the years that I've been doing A/C work GM only required 6 oz's for the system. To much oil could also give you a problem. One other thing I would like to mention is when the system ruptures it also will blow out a lot of oil, you really should drain the compressor and see how much oil you have left, should be about 4 oz's. When ever I changed out a contaminated system after installing the new parts I would add 6 oz's to the compressor and let it take the oil through the system. Are you putting dye in the system?  In order to tell which pipe is letting go put a piece of cardboard between them. This is just ideas that come to mind, hope it helps.

[Ronnie]

... It appears the high side Schrader valve may be too short as I'm not getting a high side reading at all. ( Reads the same as low side with both connected). 

 

If the high side is reading the same as the low side, the high side Schrader valve has to be open. Otherwise the gauge would have no reading.

 

Just as info... It is normal for the low side gauge and the high side gauge to have the same reading until the the compressor starts running. Once the compressor shuts off the pressure in the high side and low side will equalize after a short period of time.

 

To solve your problem it is imperative that you know if the o-rings that are blowing are on the low side line or the high side line. That is the first step in trying to troubleshoot this problem.