Low side pressure drops off.

[2x_tom]

Good afternoon. I have a 2000 Jeep Cherokee with an ac issue I can’t figure out. The low side pressure drops off as soon as the compressor kicks on.

I was adding refrigerant every year due to a leaking evaporator. It finally got bad enough that I replaced the evaporator and dryer. The system worked fine for a year and a half.

Now I’m having an issue with the low side pressure dropping off as soon as the compressor kicks on. I tried replacing the oriface tube, condenser and dryer to no avail. Both old parts looked fine after removal. Any time I worked on it the system was evacuated, vacuumed for a half hour and charged.

The system is also not accepting an entire charge of refrigerant. It’s supposed to take about 18oz (not sure offhand I’d have to go look) and about 10 is getting the high side pressure up to where it needs to be.

The evaporator is hard to blow through, not sure if that’s normal or not.

I’m running out of things to change. It’s down to the compressor, rubber high side hoses or the evaporator again.


Thanks for any advice.

[bohica2xo]

The system is undercharged and is short cycling. You can't evaluate a CCOT system with half of the charge installed.

If the high side pressure seems high it is probably a condenser or airflow problem. Too much oil in the system will also raise high side pressures and hurt performance.

The fact that you refilled a leaker several times make me wonder if there was sealer added.

How old is the fan clutch?