Hello.! Need some information. 89 xjs Last week when putting the ac on after a few minutes the ac hose from the high side that goes from the compressor to the front radiator busted..Seems the hight pressure limit system is not working.Do not know where is he limit switch nor why this thing happened.Have any response to this issue??? Need to correct it before adding gas in the system. Where do i look or change to have ac again this summer?? Thanks Yvon

 

If the high pressure hose from the compressor to the condenser ruptured, the cause must be found and corrected. Generally if the high pressure circuit from the compressor is too high, it's caused by a restriction in the system. This could be the receiver dryer or the expansion valve at the evaporator.

The high pressure switch is usually located on the line from the compressor to the condenser.

It may be best to take the vehicle to an air conditioning or Jaguar specialist for diagnosis and repair.

 

yvon, for what you are looking at, you are going to need 2 things, a multimeter and a set of freon gauges. In short, you are going to replace the hose and then connect up the gauges to monitor pressure and then at the same time, you need to find the over pressure switch and connect a multimeter across that (should be a short at low pressures, open up at a pressure normally in the neighborhood of 600 spig). This is where you are going to add some freon and start the car. If you see the pressure build up to near 600 psig, especially at idle, then this confirms a blockage. This pressure switch really is meant to protect the compressor when you start hitting the rev limiter of your car. Otherwise, that should never engage.

Now, A check that I would do is use some compressed air and see if you can blow through the various parts of the A/C system with the exception of the compressor itself. This simple check should let you know if you have a component that is plugged and additional replacement parts are needed. I would venture to guess your A/C dryer is shot and that has collected a bunch of sediment from the interior of the A/C system and it is now plugged up. Fairly common thing with older A/C systems.

 

@yvonjaguar, if you're going to get the air conditioning system functioning properly, it should be modified to use the R134a refrigerant rather than the R12 that has now escaped from the ruptured hose. Most shops no longer service HVAC systems using R12 as it's been out of production for many years and may be expensive to obtain.

To retrofit older vehicles to use R134a refrigerant, the compressor and all system seals must be replaced to accept the higher pressure needed for the R134a.