Another AC question ?

[Redsnake]

Seeing all the AC problem questions due to the hotter weather and now I have my own question.

On my 2001 XJ the AC works but according to the thermostat I keep in my middle vent the cooling has been only OK over the past week or so. Last Summer after doing some work on my AC I was getting it to cool to about 48-52 Degrees F depending on the day and if my Jeep had been sitting in the sun all day, etc... a few factors but sill it was cold enough for me to stay comfortable too/from work and around town.

Fast forward to this early Summer... thermostat readings were around 55-60 degrees and it took a while to get there. A couple days ago it was more like 65-70 degree readings and noticeably more warm in the XJ riding too/from work. I assumed my slight leak which I thought was fixed had come back. I hooked up my gauges and was going to add a can of coolant (as needed) and noticed my Low side was ~ 25# up to 35# when raising the rpms from idle to ~ 2K. High side was 250# up to #325# when raising rpms. Neither pressure was very steady and kind of bounced a bit (if that makes sense). I hooked up a small can of R134a and after purging all the air from the lines I opened up the Low side valve on my gauges and it sucked in the entire can and the pressures didn't change much... although I was hoping the Low side would bump up to 40-50#'s... however it mostly stayed in the 30-35# range and the High side stayed mostly steady ~ 300-320# pressure.

That being said, the inside temps are now mostly steady ~ 50-52 Degrees F and the air feels much cooler. Not super efficient I'm afraid but still cooling. From what I've gathered when the Low side is Low and the High side is High... that shows a possible issue w/the "Liquid Line" or Orifice tube is clogged. Does that sound correct or is there another issue that can cause this? Should I be concerned w/the pressures I have being too high??

I'm hoping to get by another Summer w/my current AC system in tact but I may end up just replacing everything... compressor, dryer, accumulator, lines, etc... I have the equipment to pull a vacuum and fill my system but I'd like to keep it going for a while.

I appreciate the advice from those who are more knowledgeable about this than I am.

 

[90xj06]

the high side can also be high when there is not a good flow of air through the condenser. try bringing it for a drive and see if you temps lower back down. on my 88 in traffic it blow about ~50 once i start driving it will drop down and start cycling to keep from going lower than 40.

i have a big floor fan i use to blow through the front of the cars when working on them.

 

[Redsnake]

The cooler vent temps were while I was driving my Jeep around town... the temps rose up ~ 2-3 degrees while just idling and parked. I also cleaned my condenser last year w/home AC Condenser cleaner and it cleaned up pretty nicely. I may do that again just as maintenance for the system.


I'm pretty sure my Orifice Tube is clogged up... but if it is, I'd be concerned that there is something bad circulating thru the system and therefore maybe everything needs to be replaced other than just the liquid line. :\

 

[90xj06]

what was the ambient temp during your drive. and what was vent temp? was the system purged of all air when the orifice tube was replaced last time?

 

[Redsnake]

what was the ambient temp during your drive. and what was vent temp? was the system purged of all air when the orifice tube was replaced last time?

I'm guessing... but the ambient temps were ~ 89-90 degrees and the vent temp was ~ 49-50 degrees. Yesterday on my drive home the outside temps were about the same and the vent temps dropped to ~ 48 or so (it felt much cooler this drive than the day before). It's hard for me to see the dang small numbers on the gauge w/out my reading glasses on these days.

As far as the orifice tube goes... It's never been changed since I've owned the XJ and I'd guess it's original to the AC System. I'm not the original owner but the AC Compressor and all hoses look to be original. I've owned said XJ ~ 6 years...

 

[90xj06]

has any service been down on the ac before hand? try cooling the condenser with a garden hose while checking pressures. it may still just be a little low. just struggling with air flow over the condenser with increased idle.

 

[Redsnake]

About 3 summers ago (before I bought some nice gauges, vacuum pump and other AC equipment) I had my main mechanic I use when I can't do something look it over. He believed at the time (via a sniffer of some sort) that my Evaporator core had a slight leak. At the time he had for whatever reason opened the system up and so he replaced the Receiver Dryer/Accumulator. I know that the Compressor, Condenser and Evaporator Core were not replaced at that time... but he did do a refill. Shortly after that my coolant leaked out a bit and so I ran some Red Angel Stop leak thru my system which seemed to work. I had the system drained and then took it home to put a vacuum on it. It held -30 lbs for ~ 30 minutes time so I assumed it had fixed the leak. I proceeded to refill w/the appropriate amount of freon(only freon, no additives) via my gauges and yellow intake hose. It's possible I let a little bit of air in the system when filling but not much. That brings me to current... thinking my system had another slight leak and thereby adding a bit of freon would solve my issue. My main concern was from the High Side gauge being higher than I thought it should be and perhaps being caused from a plugged or somewhat plugged Orifice Tube. Hopefully I'm giving a good enough picture for those who are smarter than me to help. I guess it's possible that I'm still a bit low on freon but I didn't want to blow up my system by adding more freon if that wasn't the correct way to go. None of the tutorials I've seen have had the High Side go above 300 lbs while still having the Low Side be under 35 lbs.