Dash air coolant leak

[run2]

I have a 2002 Monaco Exec with a perplexing dash air problem. A month ago we turned it on for the first time after not being used for several months. It was blowing barely cool air and I used my gen and roof air till I could find a tech who just added 2 small cans of coolant and it was blowing ice cold. A month later the dash air had gradually gotten less cold and finally was not cooling at all again. I called a shop in a town we were staying for a few days and he said he could detect and fix any air conditioner problems. Long story short, he has it blowing ice cold again but found no leak. His shop reciept shows using a can of UV leak detector and added 4 cans of coolant. He also stated he went over all the lines front to back with a leak detector(sniffer) and found no leaks at all. I fully expect to have the problem in another month of use, and wonder if any one on this forum may have some idea of what the problem may be? I have recieved some very good advice on problems in the past and am appreciative for all the knowledge that is out there.

[TXiceman]

Have them check the evaporator core for leaks. The also need to use an electronic leak detector to check the system with the unit both running as awe as shut down. The also need to check the compressor shaft seal.

Ken

[Mike Canter]

The UV leak detector with a UV light and the special glasses works wonders at night. You have to use the special glasses. It just is not bright enough without them. The only place that is really hard to see is the evaporator in the dash and the sniffer will detect that. I have found many of a small leak with that UV dye you just have to start at one end and go to the other. It will show compressor seal leaks and all. If it is leaking that much it is spraying out UV dye.

[run2]

Thanks for the replys. I was not able to be present when the tech was doing his inspection and trouble shooting. I only have the information that he related to me after doing the leak checking and the bill for labor and supplies. I am no longer in the area and hope to use the advice I have recieved here so I can be more knowledgeble next time I need service. It is hot here in the TX panhandle!

[Mike Canter]

No rain there in the Panhandle either. You can buy the UV light and special glasses at a lot of autoparts stores. I saw them at AutoZone the other day. You can also buy little cans of UV dye to add to the system

[TXiceman]

I have not seen many good techs lately that will take the time really look for a refrigerant leak. Some of them can be hard to find, even if they are really spewing a lot.

I would depend more on a A/C man than I would the typical RV A/C man.

Ken

[Wanabee FTer]

At our shop the techs would add the dye and do the sniff test. Typically the sniffer would find leaks that took one week or less for the freon to leak out. Otherwise they had me tell the customer to come back when the a/c was not cooling to re-inspect for signs of dye leaks by checking the a/c system externally with a black light.
99% percent of the time we could locate a persistent leak on the second visit. Some of the most difficult to find were slow leaks inside the evaporator suitcase. We usually found those by using the black light at the a/c condensation drain under the vehicle.

[run2]

Thanks again for the replys. I am pretty sure I will be going back into a shop in a month or so and will use the tips and information you have shared to try to get the problem resolved. Mike, I may price out the light and glasses to try do a diagnosis at night. Thanks for the tip! I am going to try to find the best AC repair shop possible but just dont know where I will end up at the time when the AC needs service again. If there is a leak in the evaporator core, is the common practice repair or replacement?