loosing freon dash air

Get one of these or pay someone else to find the leak. Freon leak detector

Get a can of fluorescent leak finder dye, a cheap LED UV light and more 134. If you can't find it then, you can't fix it.

Matt

Alone with the dye, check the fitting for tightness. Also check the high and low pressure ports for leaks, A drop of ref oil on the schrader valves needs to be done. Most schrader valves can be replaced.

(1) Freon contains light oil, there should be a very noticeable amount of oil near where this leak is occurring.
(2) Most leaks occur at the service ports because the schrader valve doesn't seat properly or is loose.
(3) Outside of the shrader the leaks occur and fittings.
(4) Get yourself a container of water mixed with dish soap, put freon in the system and paint the ac lines with the soap mixture, if there is a leak it will create bubbles.

look at front of compressor(belt end) if its oily and greasy leak could be compressor seal.
a leak of this size should not be hard to find.

To answer your question directly you can by a kit from any auto parts store. I bought mine from Advanced Auto for $20 which had the dye, stop leak, and a UV pen. The dye in with 134 shows yellow under the light. Having said that you can look at the fittings, switch, valves and see if there is any oily residue first wipe it all clean with a rag and see if anymore shows up. The major leak that I found was at the trinary switch which I replaced. I also had to tighten the Schader valves. That was about 5 years ago and it is still cooling well.

Thanks for the help. Roger

if all the lines are oil free at the connections and the compressor is oil free, it's usually the evaporator coil. With that much leakage there should be oil residue somewhere.

When I bought my 2004 motorhome, the dash air was not working and charging it only worked for a day. In my case, I found it was an o-ring where one of the hoses connected to the heater/A/C unit in the dash. On my Fleetwood Flair, it was accessed by removing the panel under the dash on the passenger side. I was afraid the evaporator core had failed so I removed the entire box (was fairly easy), opened it up and looked. Taking it out I'd noticed oil on one of the hose fittings (as mentioned in an above post). Once I was convinced that nothing was amiss with the evaporator, I put everything back together using new green color o-rings from Autozone. Evacuated the system, recharged it, and after a year it's still working well. I bought a vacuum pump from a national chain tool store, harbor something, a while back and it has more than paid for itself. RVs are pretty easy to fix A/Cs on as all the parts are easy to get at. If you have a hankering to learn A/Cs, it's your golden opportunity! Most likely you have a Denso A/C heat unit. Denso has a great free service manual that even teaches A/C operation. Worth hunting for and downloading. Probably most RV A/C issues are the old o-rings getting hard and leaky.