Annoying AC question/problem

hscrugby

Well-Known Member
Joined
Mar 22, 2005
Location
Raleigh, NC
History first, current issue problem at bottom.
OK, so since ~03 (when I inherited the jeep from wife) the AC has been spotty.
First year filled it, and it worked fine for about a year.
Second year filled it, and it stopped working immediately. (next day)
Paid way to much money for their diagnosis, refilling, checking etc, and it stopped working again.
They "guessed" it was leaking at the evaporator. Since they couldn't see it. Cost for the quote was VERY anti me getting it fixed.
So I waited ~2 years, and well, fat guys should have AC.
So bought tools, vacuum pump, etc etc and replaced the evaporator myself. Pulled vacuum, filled it. And it mostly works.
It occasionally "pops" and the compressor stops working. Pull a full vacuum again, flush everything, put oil and then 134 in and pray.

Current problem
It still doesn't always work. I cut the AC on and the compressor doesn't kick on. If I have gauges on it, the readings are fine, I tap the compressor, or more accurately the clutch/wheel/pulley on the front and it starts working.
When it's working it blows fairly cold, not quite as cold as it should, and pressures aren't quite as high as they should be. (Don't remember actual numbers but like instead of 40 I'm getting 44 at the vent, and instead of 300psi on the high side i'm getting 250)
So it seems to me the solenoid or something in that clutch is going. Only issue I can't really find a replacement for that clutch kit for less than 150-175. New compressor with the clutch is 230.
Am I missing something obvious other than the compressor/clutch that would cause this issue?
If I do find a cheaper clutch kit, is it a chance that the compressor is messed up some from the 2 years or so it had a leak at the evaporator? (If I can't find the clutch kit for cheaper, it's worth 60$ for the whole thing in my mind easily)

thanks for any help.
And my coworkers will thank you too.
 
several things can cause the compressor not to engage/come on...
1- low on freon. freon should be charged and the press should be read while the compressor is engaged/running.
2- low press switch bad. i.e. causing the compressor to think it is low on freon. some vehicles have more than 1. check them all. easiest way to tell if its bad is to jump it out and see if the compressor engages. read the press while the comp is engaged and see if you are really low. if you are, then remove jumper before you fry compressor. if you aren't, then replace low press switch
3- as you guessed, bad clutch. might be the problem, might not. one of the harder ones to tell.
4- bad a/c on switch in the cab.

when you replaced the evaporator, did you replace the orifice tube? always a good idea. if you did suck some moisture in the system, that could be the problem as well.
 
x2 on the orifice tube as its also a filter screen and junk will collect there..

im definilty not an expert but have messed with my own vehicles vs spending the $ shops want. Your pressures sound about right but that all depends on the ambient temperature. Google for a chart to lookup the correct #s. And based on the vehicles I've done. My advice is, if you crack the line\hose open, change the o-ring. Drawing a solid 30 vac for 30+ min should draw the moisture out or if your system has been sitting open for a long time the dryer can't hurt..

as said above check all the hi\low switches etc.. One of my vehicles had a bad connector plug that went onto the hi\low switch, a little tweak with a tiny screwdriver fixed the socket..
 
Yea, replaced pretty much everything.
:)
and pulled vacuum for a good long time. (probably only about 20-30 minutes cause I'm impatient.)
Only things I haven't replaced are the compressor and condenser.
I don't remember the pressures right now, cause I'm sitting at work :)
I had the chart from the fsm in front of me when I was checking them and saw temp was just not quite as cold as it should be, and the high pressure was just a little low.
Its the tapping on the front that makes me lean more towards the clutch/compressor.
But I hate shotgun approaches to problem solving when it's a 230$ part.

(Then again, anything is better than the 1400 or so from the shop for JUST the evaporator)

I guess I could jumper the switches and try. The main issue, is that sometimes it comes on, and sometimes it doesn't. So hard to troubleshoot.
:(

bleh.
 
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