Working on my son's '95 X300 and I am stumped. I replaced a bad AC relay behind left front fender. AC worked fine last year, but relay was giving the condenser fan a hard time. R 134 was low so I hooked up the gauges and put in a can and a half. Compressor runs, fans are running, High side is hot as normal, but low side is warm. No cold air and if I push AC button, compressor shuts off and red light over button doesn't light. Auto button turns on compressor but no cold air. Any ideas?

 

I'll wager odds that the desiccant bag in the rec/drier ruptured and the 'beads' are in the line from the Rec/Drier to the exp valve!!!!!!!!!

You will have a bunch of flushing/backflushing to do if this has happened.

What do the gauges indicate???? Correct pressures on low/high gauges?????

You can feel the lines all the way along to see if the temp changes in the piping.

bob

 

Yes. Need to know the high and low side pressures with compressor running, engine turning around 2000 rpm, and blower fan on high speed.

 

If memory serves the low was about 35 and the high about 130. Engine at idle fan on high.

 

So Bob, I guess the drier died. Are there any write ups on the procedure for flushing/backflushing and drier replacement? Maybe that's why the compressor was making funny noises. Where is the expansion valve located. Should that also be replaced or is it a pain to get to?

 

John, after work today I will check gauges at 2k RPM instead of idle. Thanks for all your help guys.

 

I suspect system is either still low of refrigerant charge or like previously suggested could have a low side restriction. Knowing what the system pressures are at full operating speed is imperative. Also when you are measuring the pressure at 2k if you could also determine the suction line temp as close to the evaporator that would be awesome.

 

There are write-ups on this forum every Spring and Summer about the rec/drier failing and the procedure to remedy. I think aholbro1 described his repair.

The Jag dealer (and many repair shops) remedy is to replace the drier, pipe from drier to firewall/bulkhead and the evaporator matrix (or at least the expansion valve mounted to the evap unit). Jaguar sells the expansion valve as part of the evap unit. The exp valve is NSS (not sold or serviced separately) from the evap unit.

The valve is available from aftermarket suppliers BUT............ You need to remove the entire dash to get the climate control box off the bulkhead to fit the valve. Pretty much same labor for valve or evap unit.

I would buy a can of A/C system flush and purge the (disconnected) line from the drier to the bulkhead and backflush the EVAP unit to get the desiccant beads from the short line (valve-to-bulkhead).

I have had to do this and THEN fill the system and operate the A/C. More beads found their way to the valve and I recovered the refrigerant, purged and backflushed the system AGAIN!!!! Refilled and operated. Sometimes I have had to do this several times in a row. The refrigerant oil causes the beads to stick together and to internal parts.

Compressed air and flushing fluid can be used successfully, but you will need patience.
The beads rarely get through the expansion valve because the orifice is SMALL. They can lodge in the valve so (as stated earlier) you might have to flush several times.

You can just replace everything if money is not a concern. That is what the dealer will advise.

bob

 

OK lads, so I fired up the patient and let her warm up. hooked up gauges and a can of R134. opened everything up and set on auto, temp 67/ lo and no joy. Compressor wont kick on. Readings were Low 85, High 80. Fans on radiator at full speed. pressedAC button, nothing. Back to Auto, rev up to 2KRPM, nothing. Since the compressor was working fine the other day and now nothing I'm thinking messed up drier. What are your thoughts? I tried to get a temp reading on the high side but without the compressor running, what's the point. Any help warmly welcome.

 

Ah... complications. Jacked drier shouldn't cause compressor not to operate. Need to check and see if voltage is present at the compressor clutch pins, with a demand for cooling there should be nearly 12v present. Doubtful that the high pressure protection switch is holding it off but is possible, I had pressure switch fail on my old X300 XJ6.

 

Can the high pressure position switch be bypassed to check the system?

 

For sure. Just use an alligator jumper or a small piece of wire to jump between.

 

Mine gave out in Lake Havasu AZ in July, hotter than the 3rd level of hell. I bypassed with a wire nut and about year later finally got around to replacing it.

 

You can force the compressor ON by putting a 'jumper' in place of the compressor relay behind the right headlamp area in the engine compartment. (unless there is no power to the 30 terminal on the relay)

You need to find out why the compressor is disabled. There are sensors, switches and fuses in the circuit.

bob