A/C problems

First, stop going to JiffyLube... They have ruined more good vehicles than anything else. They can't change oil properly, so no way they can do A/C service right either.

I'm guessing here, but consider a fault in the blend door allowing heated air to mix in improperly.

I don't think it is the compressor...

I'd suggest a competent A/C shop. Yea, I know those are hard to find!

Sounds reasonable. I hope you're right.

Rick

From the sympthoms, I would first guess low refrigerant charge. Per PeterD's suggestion, find a competent a/c shop and have them check it. Low refrigerant will cause freeze-up in several places, mainly in the expansion valve, but you need someone who has the right equipment and knowlege to get the charge right, especially with R134a - too much is as bad or worse than not enough and it's not real easy to figure it out unless you start with an empty, pumped down system.

Beware of one money pit: regulations require that the shop fixes the leak before re-charging. If you get a serious attack on your wallet about "finding the leak", you need to find another shop. A good shop will sniff the system then bring the charge up to spec to retest unless it's pretty much empty. That's not too expensive but a lot of places see any potential "leak" as a money tree!

Yep, that was my first guess too and that was the first thing both shops hooked up and checked. I'll go with PeterD's skepticism of Jiffy Lube but the dealership guy has a reputation for being top notch plus factory trained with diplomas and certificates plastered all over the waiting room walls. So I'm guessing his gauges didn't lie to him. And he's the one that guessed it could be the compressor clutch going bad. I didn't get a chance to talk to him directly though or I would have asked him about other possibilities.

I have one more shop I'm going to try. It's an independent Jeep guy but not an AC specialist. You'd think there would be a specialist here of all places, I'm in the deep south. But two of the best ones nearby blew away in Katrina and didn't come back. I'm thinking though that any of these shops will be able to figure it out if I can just get it to do its flaky act while it's right there in front of them.

Thanks for the response though.

Rick

Depends on the state.

EPA does not require this.

Make them quote the reguation.

Yep.

Still though, a well maintained system should _never_ go down. Most common clulprit is the bayonette connection at the AC compressor due to vibration. Just remember to never overtorque the bolts. Dead giveaway is dirt accumulation. That's due to dust sticking to the oil that gets out with the refrigerant.

For ref, I have only had to add R134 to my 1993 ZJ once. And that was due to engine vibration loosening the connection to the compressor back in 2003 or so. Replaced the O rings and put a bit more in to blow out any atmosphere, then filled it up. A little over 104 today and the AC was working like a champ.

Typical failing clutch symptoms. Easy to check, too. When it stops working, pull over, leave it running with the A/C on, open the hood and look at the compressor clutch. If it's engaged, that's not your problem. If it's not, grab your favorite tool (hammer) and tap the compressor near the clutch. If it engages, you need a clutch. Pretty common occurrence on an XJ. Clutch can be changed separately, too.

Jiffy Lube? Wouldn't even let them change my oil...

I'm wondering myself. My car does this exact thing. Blows nice and cold for 15 to 20 minutes, then the compressor won't click. The car will turn on the fans and speed up the engine, but no click and no compression. I can't get AC again unless I stop the car for a few hours, then 15 to

20 minutes again. Before it won't click anymore, the compressor is slow to engage. I've heard everything from TXD to water in the lines to bad clutch. It's a clunker car so I don't want to spend a fortune, I just want some AC for our sponge bath air here in Baltimore!

Right now it's 80 degrees out but it just rained so we're close to the dew point, and no breeze. You start to sweat in about 2 minutes out there...

A marginal refrigerant level (low, but just above the low pressure cutoff) will cause this to happen. The system, when cold has less pressure overall, and the low pressure switch then cuts off. After the system warms up (say it sits for a while) it then starts up again.

>

It's not low. It's a 23 oz system and I just put a can and a half in it. It has a real slow leak so I have to fill it every summer.

What do the running pressure gauges show, both high and low side?

Well, the third time was the charm. I pulled over as soon as the cold air quit and sure enough, the clutch had disengaged. So I tapped on everything that the hammer could reach but the clutch just never would engage. So I drove on home, 5 minutes away, found a screwdriver and used it and the hammer to bump the clutch face over in the direction the belt was turning.... bingo. It engaged on the first tap and I was right back to having cold air. Nice call Mr Bllsht :-)

Now the question is, what to do next. The dealer wants $1000 +/- to replace both the clutch and compressor. Almost as much to replace the clutch alone. Is a compressor clutch something that a jackleg like me can replace without specialized a/c tools and such? OR.... instead of the dealer, I think I can get a much better price from an independent mechanic who owns a Cherokee of the same vintage as mine. I'm thinkin' he's more familiar with it than any other independent guys around town. I don't know how much he knows about a/c though. Any suggestions appreciated.

Thanks, Rick

I'd suggest an independent AC shop with a good reputation, not a dealer. Not any shop, but one that really knows how to do AC work, as replacing either the clutch or the entire compressor requires skills that someone who is just a mechanic won't have.

ugh.... I was 'fraid of that. But thanks...... Rick

Just annecdotal, but I had my compressor completely apart last Spring. The only "special" tool (aside from the a/c gas stuff) was a good pair of internal/external snapring pliers. The clutch itself - to the best of my memory - didn't even lose the pressure. The seal there is on the shaft at the front cover that was leaking here, so I wound up doing the whole thing. The parts costs for all the seals, lube, and R134a was under $75 and it took me about 6 hours to change everything out. That included a lot of messing around with the receiver and hose seals. I already had the guage manifold and a compressor/vacuum setup. My original idea was to grab a duplicate compressor from the wrecking yard ($35) both as spare parts or maybe as a potential swap. It also served as a dummy since I had never had one of those units apart.

You can find the parts diagrams and instructions for those Sanden compressors online. That should tell you if you can swap the clutch w/o a major re-charge effort.

I would recommend one more quick test before diving in. Move your tapping to the low pressure switch rather than the clutch itself. Also, (wearing safety glasses!) blow out the clutch housing really well. The clutch is magnetic and subject to dirt and grit. As a final step, when it cuts out, try shorting the power lead to the clutch to the battery - you may well have a bad pressure switch or just dirt in the assembly. You won't hurt the clutch if you use high pressure water to clean out the gunk. The mechanical clutch should be dirt simple: go, no-go. It should be either good or bad.

snipped-for-privacy@NoSpm.> Well, the third time was the charm.

hmmm.... looks all sealed up to me. If there's dirt in the housing, I don't see any way to blow it out of there without taking it apart. Haven't found the low pressure switch either. So after a quick read of an online service manual,

've decided this project is beyond my pay grade and the deep south inJuly is too damn hot to pinch pennies. So I think I'll dump thisproject onto somebody else and just pay da man. I very much appreciatethe comments and pointers I've gotten here though. By the way, I'm beginning to wonder if you can even buy a clutch separately from a compressor. Everything I've found online so far for my model Cherokee comes with the compressor and clutch bundled together. I found a separate clutch for a different year model but it cost almost as much as the compressor/clutch combos I've been looking at.

Rick

HeBeJeepN wrote:

I saw your message yesterday but I couldn't answer because the AC wouldn't even kick on when I got home. Today I turned it on a few miles from home and it worked...right until I packed the car! On someone's advice in this thread, I took the hose and squirted the clutch top, side and bottom, then top again. (motor off, of course). It fired right up after that!!!!

So I grabbed my new Harbor Freigh R134A gauge and hooked it up. Readings:

LO/HIGH

28/155 on fresh a minute or so after power up 28/165 on recirc a few minutes later 30/160 after being on recirc for 5 minutes and the air blowing from the duct closest to the evap was 43 degrees. I'll blast it with compressed air later when it cools down some from the Texas type weather we have right now!

90 degrees and humidity to match! (actually the NWS says it's 91 & only 43%) As the temp falls, it will get close to the dew point, so it's a good thing I have a trail cover for my '97 TJ with a three piece suit on it!

It looks like this except mine is emerald green and spice:

(had to put some Jeep related stuff in the Jeep NG!)

As a follow up, I went out to the store tonight and it played well. I even got at least 40 minutes out of it after getting home and putting my food away. It got so cold, I was cycling it. 30 some minutes later, no more click. About 10 minutes later, it decided to work again. Should I use a 4 oz can of the old style electronics cleaner on the clutch followed by compressed air. The cleaner is the stuff that was banned years ago but I found some at a clearance type store and stocked up.

How come R134a went up from $5/$6 a can to the $15+ it's at now? Glad I stocked up on that, too!