chrisl757

Hi all,
2001 XJ, stock. I redid the AC last year (New orifice tube, Evap, compressor) and took it to a shop to vac it down and charge the system.

No issues until now.

When I turn the AC on, I am not feeling any cold air. It blows ambient temp air basically. I can see and hear the AC clutch engaging. I thought it might be low on refrigerant from a leak somewhere, so I connected the a/c charge kit and the gauge showed the system is at a good pressure.

One other issue is that I do not see the Aux Fan turning on.

How can the clutch engage on a properly charged system and I am not getting cold air?

Thanks

4.3L XJ

It can be low on refrigerant, despite what those cheap gauges say. Let it run for a few minutes with the hood open. The evap hose fitting at the firewall and likely at the compressor should be drawing moisture out of the air and get a good sweat going. If not, it is not cold enough. The other possibility might be a blend door located behind the console that might not be working. You cat get to that and operate it by hand to check that

chrisl757

Thanks for those ideas. I just ran the A/C on high and I could feel the lines getting pretty cold. I also plugged the refrigerant charger in to read the pressure, and it seems to be cycling in the right band. I could put a little more in there before it gets to the "red zone."

I also went inside and switched the climate control from hot to cold and back several times to see if the blend door was working. When I cycled it to hot, it definitely warmed up big time. And when I went back to cold, it cooled off (but not that cold). I can also hear the slow noise of the blender door as it responded to my changes on the dash panel.

So...I am guessing maybe I should put in a little more refrigerant? Is it possible that the blend door is not seating all the way...so that it mixes in hot air?

Thanks for listening to my stupid questions.

jordan96xj

If the lines are pretty cold, but the air in the cabin is not, then I would not add refrigerant. If the compressor clutch is kicking on for awhile (not kicking back off immediately or after a few short moments), that is a good sign that the pressures inside are at least in the right ball park. If the system is low on refrigerant, the compressor won't kick on at all or won't stay on very long (there is a pressure sensor that checks for that).


Also on a 96 and below the electric fan comes on anytime the AC is engaged. However, I don't think this is true for 97+ models.



Sounds like you have a blend door issue or some other airbox issue.

chrisl757

Hi,
I just went and monitored the pressures again, and the compressor cycles on and off pretty rapidly. Like 3 seconds on, 3 seconds off.

I seem to remember it would have longer on off times before?

Even though the lines are ice cold, the temp is just barely colder than ambient temp.

For example, if I just shift the dash panel to the vent setting (not the a/c setting), I get basically the same temp. This makes me think something is wrong with the blend door?

Very frustrating.

PatHenry

Re-read Jordans response. If the compressor is kicking on and off quickly then the pressure is not correct in the system. The fact that you got hot air when switching between hot and cold means that likely the blend door is ok (or pretty much ok.. at least, that's NOT the problem.).

chrisl757

Yeah, I see what you are saying. The blend door seems to be working.

For what it's worth, pressure cycles from a pretty high (but not redline) amount to a pretty low amount.

Maybe there is a leak somewhere? Any other ideas on what to check?

jordan96xj

It is this statement that lead me to suggest that you should not mess with the refrigerant or compressor. If lines are ice cold, then it must be determined why that "ice cold-i-ness" is not getting into the cabin. Blockages, blend doors, etc.

chrisl757

Ok, I went back and checked it again.

The compressor turns on for 3 seconds, off for 6 seconds. Pressure cycles between 25psi and 50 psi on the charging port.

The compressor sounds like it is running normally.

The air just isn't that cold. Maybe I will put a thermometer in the blower vent to measure this.

I also crawled under the passenger dash and watched the blower door arm rotate as I changed the temperature control. It seems to have about a 90 degree rotation and that is likely good enough to work.

I also felt the lines going thru the firewall to the evap. One of them is ice cold (almost too cold to touch), and the other one feels about ambient temp.

I'm hoping someone would know if this is normal? I just replaced the evap and heater core two years ago.

Thanks again.

chrisl757

I also replaced the blower fan last month with a new one. The blower works fine...I replaced the old one because it was dying on me.

TwistedWrench

That compressor is is cycling way too often. Low on refrigerant/air in system. If it was working before and now its not... You have a leak, plain and simple.

Adding more isnt going to help. Find the leak, fix the leak, vacuum the system down & recharge.

dzywicki

If your electric fan is not coming on that will definitely cause the the temps to not be as low. I had this happen when I redid the AC on my 99. The electric fan was brittle and broke when I was taking it out to get other things out. I got everything done but did not have the electric fan back in. I didn't think it would make a difference but it did.
You can check your electric fan by connecting 12 volts to the terminals when you disconnect the plug. It's a simple DC fan and will spin if it's good. I had one where the motor just seized after 19 years. To test things while my fan was out, I happened to have one of those blowers from a blow up water slide. I put it right in front of the condenser an turned it on. I saw the high side pressure drop and the vent temp dropped as well. Everything was good once I got the new electric fan in. You really do need that airflow. Similar to a house AC system with the giant fan moving air across the condenser.

chrisl757

I put in a new electric fan last year, but I don't hear it running at all. I forgot to check that. I think in the 2001 xj, it has a temp sensitive switch. This is making me wonder if the electric fan is running at all?

chrisl757

I can see what you all are saying though. If the compressor is cycling this fast, I have a leak issue elsewhere. If the fan isn't working, I don't know if that would cause the compressor to cycle that fast.

4.3L XJ

The fan would have no effect on the compressor