My Daughter's Cherokee (4.0/auto, 1999) has an AC leak.

I filled it (worked fine for about a week, then the AC started cycling again too frequently).

I put dye in with that fill. The only place I'm seeing the dye is at the low side quick connect.

(I don't know where to look under the dash, so that's possible, but I used a high power UV flashlight after dark, and followed each pipe and fixture with no evident dye).

The low side would get some dye during the filling process, but I also wonder if the Schrader valve is leaking.

Does anyone know what the proper valve size is?
The proper cap? (A cheap amazon one doesn't fit, and trying to take one from my 05 Wrangler didn't work either.)

Also: Has anyone used the tool that has a valve to keep from losing all the coolant? Looks like there's a few sizes.

Thanks!

 

For the UV dye test, make sure you're in a dark area. If you're looking for the leak from the evaporator, check the evaporator drain tube. Also check behind the compressor pulley. The uv dye at the low side fitting could be residual from charging. The dust caps really don't seal the refrigerant in either. They just keep the dust/dirt out. With that in mind, that could be the source of your schrader valve leak of dirt got trapped when it closed.

If it does turn out to be your schrader valve, the core removal tool is sold at parts stores. Get it out and bring it to the store. They should be able to get you a replacement.

 

As far as the core goes, it is about like any standard schrader valve core. But I assume you are looking at a tool the will extract the core and not loose the refrigerant. I assume this is what you are referring to


Yes they work. Remember there is a different size for low and high pressure valves

 

I was outside after dark, so could see very well (including glow from the oil dipstick handle, tags glowing white, etc.). Nothing behind the compressor pulley (checked the whole compressor over well). The only glow (from the dye) was at the low side...so it could be from the dye going in, or from it leaking out. I may clean it tonight to the point I don't see dye and give it a few days to see what happens.

I'll check the drain tube...good point, thanks!

 

That's the tool.

 

I have a leaky schrader valve too, so thanks for this thread.

 

When I was troubleshooting the leak on mine it was the evaporator. Found it in about 5 mins using a refrigerant leak detector.

 

If you're going to do your own AC work, you'll need the proper tools.

It comes with the leak detector, vacuum pump, gauges... everything you'll need to do the job. Or, that's about 1.5 hours worth of labor charges at any shop. Your choice.