Fixing to need AC.

[Knucklehead97]

So been driving this new Jeep a little bit. Haven't drove it far but it seems to be doing perfect other than a roar coming from the rear when I get up to speed. There's a few little things I want to fix and the only one that I have no experience on is getting the AC fixed in it. Heat is amazing but the AC is just air. I personally don't care for AC but I recently started going out with a girl and I would like for things to be more comfortable for her in the Jeep. Where should I start on figuring out what is wrong with the AC?

[dboisen]

First you will need to find out if the clutch engages

 

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[Knucklehead97]

I cranked it and turned the AC to max/cold and nothing changed. Still blew hot and didn't hear any different noises. I read somewhere that the clutch will not engage if the freon is low?

[Knucklehead97]

And from what I have read so far, I really should just go ahead and convert to 134a or whatever the new refrigerant is called? What exactly is required to swap?

[Marine1Texas]

if the Freon is low the pressure switch that is on top of receiver will not allow power to turn the compressor on.

If it was the old R12 system, and your converting to 134a, I would replace all the orings, the receiver, the new 134a High and low ports.

You will need to add the PAG oil also. Inspect your hoses to make sure they are going to last, nothing worse then converting and 1 year later a leaky line.

Some will say only needed is orings, Freon and oil. receiver is always best to change when opening a system up also you will have oil from the r12 system trapped in the old receiver.

after you change everything out, make sure to vacuum the system down and let is sit for 20 minutes or so. that way you know you have not even a small leak. Once you are sure add the PAG oil and the 134a after that.

[Pete M]

I would start with an r-134a adapter kit. 

 

AC issues are hard to diagnose without the proper gauges and tools.

[Knucklehead97]

Is the adapter kit a universal thing or per vehicle? And will I have to change the compressor to a 134a compressor? I'm completely clueless on anything involving AC systems so this will be fun haha

[Marine1Texas]

134a kit is pretty much universal. new connectors with Freon, and pag oil.

 

From what info you supply which is not a whole lot. I would make sure your not already converted to 134a. I am assuming the age of your vehicle it was converted over at least 10 to 15 years ago.

Left is the R12 ports and right is 134a ports. That way you know what you have. If your already 134a then you need to check your Freon level. Get your self a small gauge that screws on the top of a 134a can, you can normally pick them up both for around 20 dollars.  At Walmart they sell 12oz cans for 5 dollars, you can try to add a can or 2 to see if you can get it going. Never the less if you have to add Freon you have a leak. To test if the compressor is working at all jump the wires on the pressure switch. you will know right away if it is working or not. don't jump it for long, you don't want to run a compressor with low Freon.

 

Normally I recommend when you have a leak anywhere in a a/c system, you replace receiver all the orings, and inspect the hoses for cracks that can be a leak. I think if your going to do it do it right so it lasts. Harbor freight sells a cheap manifold kit and a cheap vacuum that you hook up to your compressor. With a oring kit, and a new receiver you pretty much good to go.

[Knucklehead97]

Thank you for showing me the difference in ports! Just ran out to install the grill the correct way on my lunch (PO was an idjit) and checked the ports. It's already set up for 134a apparently! I'll check the compressor soon and go from there

[75sv1]

Thought I add to this. I had my compressor seize up Saturday. Fortunately it was in the driveway and not on the road. It was giving me signs most of the day. The motor would run, but the belt didn't move. The compressor was locked up. I took of the AC clutch. The bearing was shot. Looked like more than a few ball bearings were missing. I did a search on the net and Ebay. I could only find the AC clutch rebuild kits on Ebay. All the parts stores didn't list them. I bought a bearing off of EBay. Then I saw Auto Zone had the bearing. $22 or so. I couldn't press out the bearing, so I turned it out with my lathe. I pressed in the bearing. When assembled, the coil pack binded on the belt pulley. I turned the end shorter 0.020 or so. I finally got it together. Still, have to assemble back the other stuff. Need to get a new belt.

[Knucklehead97]

The compressor locked up on my Contour before I bought it. The PO just bypassed it with a shorter belt. So basically my contour has a fully charged system ready to go if that compressor wasn't locked... sadly have to depressurize the system to change the compressor. Haven't decided whether I'm going to fix thr AC and heat in the Contour yet, though. Back to the Jeep. My plans are to borrow a vacuum thing from Autozone to test for leaks. If signs of a leak show then I will probably get a cheapo DIY freon kit and some dye (can you do the whole dye thing yourself?) And go from there. If it's a small leak, maybe the freon I add will give me some AC for a little while.

[Marine1Texas]

yes if the leak is small it will work for a while. I do a/c repair my self it is part of my business in my company, and I never never never ever do dye. you can not get the dye out of the system unless you replace every part. the dye will interfere with the total cooling and heat exchange, and there is no way to vacuum the dye out of the compressor completely and you will need a receiver as it will cut life of it in half. To find a leak, you are better off filling with nitrogen and using soapy water.

unless I am doing a unit that is a b*@$£ to get to all the connectors. I just go ahead and change all the orings.

 

I am not saying there are not other ways of doing leak checks, but doing things the right way does not always cost more money in the long run.

[Knucklehead97]

Great! Seems like I have a plan. Glad to have someone who actually repairs AC systems around to give me tips. This week I'm buying a radio/speakers/subwoofer then next paycheck I will be working on the AC! Been DDing this Jeep since my brother needs to borrow my Contour. Not having a radio is getting VERY annoying. I'll update ya'll when I get to working on it!

[Pete M]

I bought a radio with bluetooth/usb/aux, and rca outputs (no CD player) for about $20 on ebay.  only issue has been I didn't pick one that also dims the radio lights.  :doh:  

[Knucklehead97]

I threw about 50$ towards a Pioneer radio because I LOVE the one I have in my Contour. And 90$ for a set of front and rear Kicker speakers. Haven't quite decided on a subwoofer yet, looking at a kicker 300 watt RMS 10" with a VM amp in a ported box. The MTX 10" I have in my other Jeep in a ported Kicker box absolutely DESTROYED the small cab truck and it was only running at 250 watts peak. I definitely have to run a bass knob though because the girl I am talking to is not a big bass fan like I am lol :D this Jeep is so nice that I'm trying to put nice quality equipment in it and set it up good. Hence one of the reasons I'm actually going to get the AC fixed in it :D

[Keyav8r]

When I bought my 91 the AC worked very well. After siting idle for most of the winter while I did some floor repair, interior cleaning, inner fender liners replacement, etc. the AC now just blows ambient air on any setting. After I jump out the pressure switch to check for compressor operation I will need to check the pressures on the low and high sides but I have no idea what those pressures should be when operating normally and what the minimum pressure is to operate the pressure switch (I have a set of refrigeration gauges to check pressures). If it turns out to be just low system pressure I'lll put in some more R134a (system appears to have been converted based on presence of fittings). If that doesn't do the trick, I'll pull a vacuum, see if it holds and (a) if it holds, change o-rings to make sure they're right, change the dryer, vacuum again, and add PAG oil and R-134a, or (b) if it doesn't hold, track down the leaks (hoses look a little suspect, praying that the coil in the cabin doesn't leak), fix them, then do the vacuum test again, add oil and freon and hopefully have AC again.

Can someone tell me what the pressures should be (low side, high side and minimum for pressure switch to allow compressor operation)?

[Marine1Texas]

the pressure switch will not activate below 45 psi. + or - 2 psi you can check static low side. The low side while compressor is on should be between 27 and 40 PSI ( do not exceed 40) . If the out side temp is hotter the higher the psi should be. The high port should be 225 psi to 250 psi.

 

if you check the static psi, that means when it is off. both sides should be very close to the same psi any where from 75 to 100. if your static psi is lower then 45 the pressure switch will not allow it to kick on the compressor.

 

(a quick Tip)

You can begin testing with only 45 psi. You won't get any cold air, but you should start to see some compressor engagement. As soon as the compressor engages, it will cycle off rather quickly when the suction side of the compressor draws the pressure on the low side below 20 psi.. You will see the low side gauge at 45 psi, drop quickly to 20 psi, at which point the compressor will cycle off. Then the low side gauge will climb back up to 45 psi as the high and low side equalize. At this point, he compressor will kick back on and the cycle will repeat itself. This is called short cycling. This rapid cycling of the compressor is a good indication that the system is low of refrigerant.

[Keyav8r]

Thanks! I think I'll go to the garage and check it out now that I have enough education to be dangerous .