ACE Dash Air

[ThorAce2015]

Last year The dash air in our 2015 ACE quit blowing cold air. My mechanic did an evacuation and recharge of the system. It lasted about 2 months and quit blowing cold air.
Has anyone else on this forum had similar issue? If so, what was the fix?

Back in the seventies I installed auto A/C systems and did the in dash installs of Class A and Class C for Shasta Industries in Simi Valley, Ca. None of the units had factory air. Of course all the units today come from the factory with A/C which makes it more difficult to trouble shoot.
Any help will be appreciated.

[HarryStone]

Sounds like it has a leak. A reputable tech would vacuum it and test the integrity of the system before refilling it.

[TXiceman]

Sounds like a leak was not found or it developed a new leak. Find a reputable tech and have them perform a pressurized leak test, fix leak(s), then a vacuum test (under vacuum for 24 hours), then recharge the system.

Ken

[MrMark52]

No way will a system with a leak hold a vacuum. And I’ve never seen a leak to be intermittent.

Problem is - it takes time to find a leak, and most tech’s want to go with the quick fix.

If the system isn't cooling, first thing to check is to make sure the coolant control valve for the heater core is fully closed, and all the air box dampers are properly positioned.

If all good there - investigate for residual signs of oil. On our ‘02 coach, come to find out that the OEM Delphi compressor had a design flaw that caused it to leak around a belly seam. A PO had apparently had the system serviced and dye put in. It wasn’t unit I had to pull/replace the compressor (story elsewhere) that the leak was visible.

Any, any, sign of oil anywhere within the refrigerant system hoses, tubing, connections must be corrected before even thinking about pulling a vacuum. Vacuum draws moisture into a system that just loves to adsorb moisture. Moisture in a refrigerant system is bad, just bad.

Note the following pressure test should be performed after the coach has sat for arpt least 24 hours without the engine running. At no time should the engine, or the compressor, be or has been, operating.

Once a complete inspection of the system as noted above has been made - get a bottle of dry nitrogen and load the system with 150 pounds of pressure. Note the exact pressure after the system has “soaked” (temperature and pressure stabilized) for at least 30 minutes. Let it sit for 24 hours, then check the pressure again. Assuming the same environmental conditions as you had the day before, the pressure should not have changed.
If the pressure went up, then the environmental conditions of the system were not the same as when the system test pressure was initially applied.
If the pressure went down, it’s highly likely you still have a leak.

It’s not until you can maintain stability in the above testing that you evacuate the system. And once again, you need to be able to hold a 500 micron vacuum for at least 30 minutes before you proceed with charging the system.

All of the above takes time - again, as mentioned previously, most shops don’t want to spend the time doing - especially after an inspection for oil has been done (which is darn near impossible when it comes to the evaporator).