Automotive Air Conditioning Information Forum

I recently changed the evaporator, accumulator, and orifice (I added 2oz of PAG 100 in the evaporator and accumulator) tube on my 2001 Jeep Wrangler. I vacuumed the system (held vacuum for 45 minutes) and filled it with 1.5 pounds of R134.

On the day I filled the system it read 35 low side 225 high side. It was about 90 degrees that day. Vent temps were about 49 degrees.

Today (again about 90 degrees) was the first day I used the jeep. The AC started out cool, after about 30 minutes on the road it was blowing warm air. 10 minutes later it was cool again but not for long. The on/off would happen as I drove home.

When I put the gauges on the readings were all over the place. From 43/250 to 75/75..............compressor was cycling on and off every 30 to 60 seconds.

Is there something else I can check before ordering a new compressor and condenser? I am sure both of these parts are original.

Would overcharging cause these symptoms? I have seen conflicting specs for the R134 (no sticker on the Jeep under the hood nothing in the owners manual either.). I put in 1.5 pounds, but now I see most specs call for 20 OZ.

I also used PAG 100 and I see the spec is PAG46, would this cause any issues?

Your compressor is cycling a lot.

1. Check your fan clutch or electric cooling fans, maybe not enough air flow over the condenser causing safety shut-off of compressor.

2. Also check the electric power to the compressor with AC on when compressor stops being engaged; maybe your AC clutch gap or oil on the AC clutch is causing poor engagement.

I had a shop remove some R134A and now it's cooling all the time. Vent temps were between 42 and 48 outdoor temps were between 75 and 84 yesterday/last night.

But the compressor is cycling on and off 3 or 4 times a minute. Is this some thing I should be concerned with? Others with the same wrangler say their compressor does not cycle as much.

I would suspect the cycling switch give the wild pressure swings you have posted.

The compressor should be running with the low side above 35psi, and the high side below 400psi.

Those switches do go bad.

Replaced the switch, compressor now starts and does NOT cycle on/off (at least for the two minutes I observed). Did have time to read pressures again today