AC recharge problems

Hi everybody, I have a 2000XJ and the AC has been giving me some problems. When the jeep is cold, it seems like the AC works fine (at least it did this morning), but as the jeep warms up or it gets warmer outside, it starts blowing warm air into the cab. I bought an AC recharge kit and connected the gauge on to the low pressure side near the accumulator. The gauge reads 110psi when the jeep is running or not, which I believe is extremely high.

I don't really know where to go from here. I thought it was simply low on refrigerant, and all it needed was a top up. what could the problem be? I bought the jeep second hand, maybe he filled it too much? I'm really at a loss here of what to even look at next. Any pointers would be greatly appreciated. I would like to get it somewhat figured out before resorting to taking it to the shop

Thanks

when taking that reading, is the compressor operating? That sounds like an equalized AC system-- where the high and low are equal. You should get MUCH lower on the low side and a good bit higher that that on the high side when it's working.

High and low should always be equal with the compressor off. I've never heard of an equalized AC system unless you're just referring to engine off gauge readings.

You really need to put a proper gauge set on both fittings- low and high side and see what that gets you. Post up the results.

JJacobs said:

High and low should always be equal with the compressor off. I've never heard of an equalized AC system unless you're just referring to engine off gauge readings.

You really need to put a proper gauge set on both fittings- low and high side and see what that gets you. Post up the results.

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exactly what I was saying-- if the compressor is not "on" (turning and circulating the refrigerant) you will get "equalized" (higher low side and lower high side) pressures.

Agree completely on the manifold gauges being necessary-- without both halves of the equation, it's just a guess.

ok I see what you're saying. The kit I bought didn't come with a high side pressure gauge, can I buy one somewhere quickly?

Even jumping the low pressure switch and swapping out the compressor clutch relay with a working one won't engage the compressor or lower the pressure reading... Is my compressor or clutch shot?

Unplug the compressor clutch harness at the compressor, jumper it to 12V.. does it click and engage?

A/C system off, and having had several minutes to equalize, both low and high should be the same reading of approximately ambient temperature. If you do this just after opening the hood on a hot day 110 on both is very reasonable.

JJacobs said:

Unplug the compressor clutch harness at the compressor, jumper it to 12V.. does it click and engage?

A/C system off, and having had several minutes to equalize, both low and high should be the same reading of approximately ambient temperature. If you do this just after opening the hood on a hot day 110 on both is very reasonable.

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ok i jumped the clutch to 12v and it didn't engage. It seems this could be a bit of a problem. Is the clutch rebuildable or replaceable without changing out the entire compressor?

and it is almost 30*C here, so I guess 110psi is ok with no compressor running

edit: I just realized I can manually engage the clutch if I jump it to 12v then push it in with my finger before I start the engine. The coil can hold it in well enough for now... When I do this, the pressure readings are in the appropriate range according to the FSM (~35 psi @ 27*C ambient air temp), although my outlet temperature sits around 50*F. Looks like I need a new clutch for starters

The connector wire to the clutch is giving it 12V, so it looks like the low pressure switch and stuff are working ok



Thanks for the help so far! That was quick!

Yep, clutch going south. It shouldn't need a push. The other thing you might try first is the air gap adjustment, can you put a thinner shim in there?

Yep!! Sounds like the "air gap" issue. You can remove one shim and likely fix it. Search it or go to the Sanden site for the manual.

Saudade said:

Yep!! Sounds like the "air gap" issue. You can remove one shim and likely fix it. Search it or go to the Sanden site for the manual.

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ah yes it was. I took the 4 bolts holding the compressor on and pulled the clutch assembly off with 2 screwdrivers and removed the one spacer that was behind the clutch plates. All is good now!

simple 5 minute fix (after I figured out that's what it was and how to fix it...) with no cost. Not very often that happens, so I'll take it when I can

Thanks for all the help everyone

Good deal, freebies are the best!