Freon leak help

On my 87 Comanche I am having problems identifying the source of my Freon leak. First thing I did was replaced the compressor with new ester based oil because my old one was froze both clutch and bearing. Then I added my Freon and a can of dye. It leaked out in no time. I opened the hood at night shined my black light but no luck. Didn't see anything except a little on the inside of the low side port from me disconnecting the Freon filler hose. I've looked at every hose, connection, accumulator, exp valve, condenser. Everything except the evap but don't know where I can get a good look at it. Help would be appreciated thanks.

The evaporator I believe has to have the dash pulled to get a peek at it, maybe there's a way to snake a camera probe to see it , I dunno.

If your old compressor self destructed you might need to either replace or clean out the lines, evaporator and condenser to get the metal shavings out.


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I took a,small peak at it by taking out the resistor for the blower but found nothing

Green Mesa XJ said:

The evaporator I believe has to have the dash pulled to get a peek at it, maybe there's a way to snake a camera probe to see it , I dunno.

If your old compressor self destructed you might need to either replace or clean out the lines, evaporator and condenser to get the metal shavings out.


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Might look around the drain if you used any kind of dye it might show up there.

I didn't think the resistor was that close to the evaporator cause the condensation would short out the resistor.

My guess is if there is no leak you can find in the engine bay it has to be the evaporator.
Condensers in front of the radiator can take a lot of damage too.


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Green Mesa XJ said:

Might look around the drain if you used any kind of dye it might show up there.

I didn't think the resistor was that close to the evaporator cause the condensation would short out the resistor.

My guess is if there is no leak you can find in the engine bay it has to be the evaporator.
Condensers in front of the radiator can take a lot of damage too.


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Definitely look around the drain for any dye, as it tends to collect there if the drain is flowing. If you can pick up a cheap endoscope camera you might could go through the vents to see if there is any dye in them.
https://smile.amazon.com/Fantronics...UTF8&qid=1496947787&sr=8-4&keywords=endoscope

Are you using the R134a or still on R12? I still run R12 in my 87 Ranger, and have a "halide detector" for leaks. It's basically a propane torch with a hose just below the flame. move the other end of the hose around, and if it sniffs the R12, the flame changes colors. I highly suggest caution using it in the interior hahaha

you can try popping open the recirculate door on the hvac box. or try taking the blower fan out and looking through there. how much freon did you put in? if it almost instantly leaks out you maybe able to hear a hissing.

Not trying to ask a stupid question but what drain are you referring to?

Green Mesa XJ said:

Might look around the drain if you used any kind of dye it might show up there.

I didn't think the resistor was that close to the evaporator cause the condensation would short out the resistor.

My guess is if there is no leak you can find in the engine bay it has to be the evaporator.
Condensers in front of the radiator can take a lot of damage too.


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There's a drain in the dash to under the jeep for the evaporator to drain the water it gets from the air.
If the ac had leak finder in it and the evaporator is leaking there should leave some sign of the UV dye. Unless it was too long ago and it's washed away



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If it went really fast, it's a leak on the high side or if on the low it would be a large hole, look at the condenser really close, could be in the tubes. Or on the Schrader valves. People forget to check them, usually because the refrigeration gauges are one them during leak testing. If it's the schrader they can be tightened and as long as they are still good it will stop them leaking.

On the older vehicles its easier to change the evap from what I understand. All the other suggestions are good as well. Personally I've only seen slow leaks from Shrader valves and if it leaked that fast while the A/C was on you probably would've smelled it in the cab. On the later models the drain exits just above the frame rail at a rubber elbow that may or may not be present anymore. It's about 1" OD. If you're compressor was tearing up, it is a good idea to flush or change what can be flushed & change ALL components that cannot be flushed. I'm not 100% familiar with your vintage, but particularly things like newer condensers cannot be flushed. Orifice tubes cannot be flushed effectively. On the later models that means buy another $20 liquid line which has the orifice tube embedded in it (cannot be removed). Evaporator, accumulator, etc. Manifold lines are large and free flowing and easier to flush. Google Black Death A/C for more information.

the renix era jeeps do not use a Shrader valve. they have 2 mechanical valves that have to be opened slightly. if opened all the way it isolates the compressor from the rest of the system. if memory serves tightening them opens them. also there is no orifice tube on the renix ones either. it has something that looks like one but its a "muffler" or so they claim.

how much freon did you put in? factory r-12 charge is 38 oz. so r-134 would be ~30.54 oz

the 2 mechanical valves are called "king valves" in case you wont to read up on them


at this point, i would say recover whatever is left in the system, and charge with nitrogen. you can leave it hooked up and running, it will keep leaking.

should be easy to find then.