Engine Size: 4.0
Refrigerant Type: 134a
Ambient Temp: 105
Pressure Low: 35
Pressure High: 320
Country of Origin: United States
I've had this Jeep for a couple years now and have been happy with high 40/low 50 vent temps even on 110 degree days here in Phoenix. This summer I noticed vent temps were high and I measured it at 66 degrees. Natural assumption was that it needed the 134 topped off. I hooked up the gauges and was shocked to see mid to high 30's on the low side, and 320+ on the high side. Electric fan was on, and the mechanical fan was pulling a lot of air also. Fans are strong enough to keep a rag pinned to the front of the grill. Figuring that the condenser was probably clogged, I hosed it down with 409 and flushed it from the back side. I did get some dirt out, but nothing significant. I can see between all of the fins, so I know this isn't a problem with a dirty condenser. Even on the interstate I am not getting temps less than 65 out of my vents.
I hit the condenser with a little bit of water (half of a 16oz bottle) and the high side pressure dropped to about 240. Within a few minutes, it was right back up at 320 again.
What else should I check? Where do I go from here?
Edited: Fri July 03, 2015 at 10:09 PM by JeepSJ
When the high side dropped, did your vent temps also come down? It appears, your engine fan clutch may be weak; make sure you have the proper charge in the system.
Edited: Sat July 04, 2015 at 4:53 AM by Dougflas
When I put water on the condenser the vent temps only dropped a few degrees. I think the lowest I saw was 63. I didn't want to add any 134 because the pressures were already at the top of the scale. I don't think the engine fan clutch is the issue - XJ's have a mechanical AND an electric fan. Both were running and both were pulling enough air to keep a rag sucked to the front of the grill. I also have a big air blower that I put in front of it just to test that theory and did not have any change in my results.
Like Dougflas said you have to be sure its not overcharged, the only certain way is to evacuate and recharge by weight. That will also ensure there is no air in the system, which has similar effects of high pressure and poor performance.
Edited: Sun July 05, 2015 at 12:29 PM by mk378
I'm having a hard time with the overcharge diagnosis. I have had the vehicle for several years and it has always worked great. I have not added any 134 since I bought it. Why would i suddenly have an overcharge condition?
Have you ever put leak sealer in it? Im a n00b so take this with a grain of salt but I would guess you have a clogged expansion valve or condenser outlet.
I have never put any leak sealer in it, but I have no way of knowing if the DSPO did anything like that. I'm going to dig into it more this weekend. I want to pull the orifice tube and make sure it isn't plugged. I've been threatening to put in one of AMA's parallel flow condensers so this might be a good time.
Measure the temperature of the input line and output line of the condenser. Output should be 20 to 30* cooler. Also, try blocking off the heater hoses. I am very suspect of the 320 high side.
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