Dash Air Refrigerant Leak Points

[Edward Buker]

I thought a good topic would be to gather the experience of owners who have had successful repairs of leaks in our R134A dash air systems so others will know some of the likely culprits to look for.

My recent leak.... I would typically add some R134A yearly due to an elusive minor leak. That has been true of all three motorhomes I have owned. I consider this just part of normal maintenance. About a week ago I went to check the charge level of R134A and I found the pressure had gone to zero lbs of charge....Funny it was working fine in the fall.

I went looking and found some oil on a hose fitting at the top of the condenser. I removed it and changed out the Oring that looked deformed and cleaned the fitting. I pulled a vacuum on the system for half an hour and checked the gauges to see if it would hold, and the system still had a leak. I then pulled a vacuum again and added R134A to 30lbs of pressure and then I then heard the leak. Nice thing about adding pressure after pulling a vacuum is that the engine is not running so you may actually hear a leak. The leak point was on the backside of the compressor. I found a pressure relief plug that had failed. They are basically a sealed plug that is supposed to release at 550lbs and do not reset. I found out that Santech has had fails for this plug that it was available through special order at Auto Zone. Check that plug before you pull it and possibly throw away a good compressor. Photo of plug attached.

I replaced the plug with the new Oring, pulled a vacuum for an hour and a half, closed the valves, shut off the pump and tested the vacuum for several hours and it held fine. I charged the system and it has maintained pressure for a week with no loss. Thought I would pass this along.

Later Ed

[George Harwell]

Thanks Ed, your a wealth of information and it is greatly appreciated by all.

[LaMonte Monnell]

Thanks Ed for that information. I had my dash a/c system inspected in December while at CAT and had pretty much everything replaced, even the low and high charge ports had minor leaks and were replaced along with a section of the high pressure hose.

It seems to work well, but all new parts so it should I guess.

[William Ervin]

I had been fighting with my dash A/C system for several years, I'd put dye in two years ago and had found no indications of dye anywhere.  This spring I decided to fix it once and for all, I started with the easy (relative term) things first.  I evacuated the system and changed out all three schrader valves (one high two low) on the front and rear of the coach.

I put a vacuum to the system and then charged it, Problem solved.  Wow that was easy

[Edward Buker]

Those Schrader or ball valves can be trouble. I have replaced the ones on my Suburban but not the ones on the motorhome. Would have been a good time to do it but that water is over the dam....thanks for bringing those up.

Later Ed

[Keith Moffett]

Had the system gone through and there was a leak.  It had started out like the one Ed mentiones just needing a refill yearly but failed completely this year.  The vaccuum showed a leak in the fitting on the bottom of the condenser.
The cure (I hope) was a new drier, pressure valve, o rings and a clean out with brake fluid.  The system took nearly 5 pounds to refill.  What had been just ok cool at best is now arctic blast!  Just in time for La Nina and highs in the low 60s all week!  LOL