After storage for 3 months, I drove my 95 XJ6VP tonight. Everything awesome UNTIL I turned on the AC and no air conditioning. It was ice cold the last time I drove it. I checked the pressure on the low side which was “0” even though the compressor was on. I added 1 pound of freon, but it leaked out as fast as it entered the system. I then put another pound in with the UV dye. Long story short, I traced every line with my black light; the compressor and the condenser and cannot find any leaks. I am hoping it is not the evaporator! I have not heard of many problems with it.

Frustrated! The identical same issue is with my Bentley Turbo R. It’s going in tomorrow.

Any help is much appreciated!

Richard

 

Thrmoexspansion valve stuck open not allowing pressure to build between the compressor output and the TXV ?

Normally they clog up restricting freon flow

See page 110 of the 703 document for a self test on the A / C control panel that may or may not show something as a starting point

There is a TSB for the fault codes but I think it's in the X308 section as the same Denso manufacture

Does the compressor clutch engage as there are problems with the interior temp sensor dirty

Does the freon line out and aft from the compressor get hot to the touch ?

Fuses for the Climate Control ECU ?

http://www.jagrepair.com/images/TSB/...stem%20DTC.pdf

 

Hi Richard,

If the refrigerant is leaking out quickly, one possibility is that one of the service port valves is leaking. If it's the low-pressure port, you may assume the UV dye there is from the process of injecting the dye into the system, when in fact the refrigerant is escaping there.

A very common issue on the X300 is that when the rubber bushings on the bottom of the condenser wear out, they allow the condenser to rub against a steel brace, which wears a hole in the condenser. It's in a spot near a bottom corner of the condenser that may be difficult to see without some disassembly.

Cheers,

Don

 

The "ball" style valves used in the X300 and many others are junk. I've had them leak almost every time I've gone into a system. They are simply not well made (i.e. Sanden brand, you know where they are made). I think the plastic in the valve's "ball" is not resistant to the R-134a and oil. Pin style Schraeder valves are much more reliable, and that is what i want to use next time my system starts losing pressure.

At my last small refresh in March, the only 3 year old high-side ball valve leaked after I disconnected the valve of the gauge set. A lot at first, but I got it to seat better, then put a metal sealing cap on it. Ok for now.

Keep in mind: if air and humidity get into the system (likely, if the system is at zero pressure) it will work against any recharge attempt. It is supposed to be evacuated with a vacuum pump first. The oil is very hygroscopic so will attract moisture if left open (or with a bad valve) for long.

A gauge set can tell you a lot about what the system is doing. It takes some time and attention to learn, but can be very useful. A vacuum pump in addition to a gauge set will tell you if the system has a leak before you put any freon in it. Both items together are what is really needed to allow you to fully and correctly recharge the system. There is a learning curve, and great care must be taken to get it all right and to be safe about it too.

So, first of all, you will want to hunt down some pin style valves for both valves. They screw right on to the hose fittings. They are a size that is commonly used in GM vehicles. I'm going to need some myself so I'll take a look on the interweb. Or, insist your service shop replaces both valves with the pin style. An easy task to take care of before looking for other leaks.