A/C Recharge

X2 to the above.

Also, remember, the only time you should ever need to "re-charge" an AC system is if you installed a new AC system component, or there is a leak.

I just put that out there because a lot of guys have AC that doesn't work (or doesn't blow very cold), and they assume that recharging it will fix it. Not the case at all, especially if you have a leak!
 
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Don't you think after 10 or 15 years you'd need a little recharge?

When's the last time you recharged your refrigerator at home? My 99 Isuzu with 195K miles on the clock has never had a recharge(knock on wood), and blows ice cold. It's a sealed system and Freon doesn't lose its effectiveness unless the system is compromised, to the best of my knowledge, which isn't much.
 
Don't you think after 10 or 15 years you'd need a little recharge?

Nope, I don't believe so. Like @bobthetj03 mentioned, when was the last time you recharged your 10+ year old refrigerator at home?

As long as the system remains sealed (meaning you don't spring a leak somewhere), my understanding is that it should never need to be re-charged. I'm not an A/C expert, but this is my understanding from what I've read.

The fridge thing makes sense too when you think about it.
 
Bought a 2002 TJ and want to recharge the a/c. Not sure what Freon is in the system. What kit should I buy?
My '00 had no cold air blowing when I bought it so 17 years old now, and I used one bottle of E-Z Chill off of Amazon for $18 and it now works perfectly and is ice cold for the first time. The stuff works great, and comes with a halfway decent gauge so you can see where your levels are before and after.
 
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One of the issues with 134A is its ability to seep through hoses. While not so common on OEM crimped hoses I have seen three different major improvements in the barrier material used in a/c hose where I work. It can and will seep out over time. In addition to hose you have no less than 6 o'ring fittings a compressor shaft seal and two switches with o'rings to consider as well. Jeeps are well know for high engine compartment temp, which over time can have an effect on anything made of rubber.
A refrigerator and a Jeep A/C system share little in common other than they both remove heat from air. When was the last time you saw your refrigerator condenser flexing as your drove it over some big rocks?
Advice above to avoid simply adding refrigerant to see if that brings it back is sound. An overcharged 134a system will perform as badly if not worse than an undercharged 134a system.
Other than low refrigerant you could have a bad high or low pressure switch, a bad rely or other reason preventing the clutch from engaging.
The best thing for you would be to have a tech with a/c training or lots of experience check you system out' if it is not electrical then he will pull down your system with a good reclaimer. If there is still refrigerant in the system a good reclaimer will tell you how much. If it shows the correct amount then you are not low on refrigerant. My 2000 4.0 system uses 1.5#. If you have less than that then you have a leak. A good tech will then charge the system with nitrogen and look for a leak. Makes no sense to charge it with refrigerant to check for leaks. After the leak has been corrected then he will change the receiver dryer, pull the system down with a vacuum pump for at least an hour, if he uses a micron meter than you have found a good tech, because only with a micron meter will you know how much vacuum you have pulled it down to. 500 microns is good. Then charge the system and off you go.

B
 
What if I can’t find an AC leak even with the Mastercool Professional UV Detector Kit? I was low on refrigerant according to the gauge. I added some, cranked the Jeep on max air. Finally got pretty cold air. Within a week it will be warm again. So after recharging I added some of the UV dye and ran the Jeep and max ac for 10-15 min. Can’t find anything with my UV light. I thought maybe it’s a slow enough leak that it won’t show up for a few days. Thought I’d keep running and checking it. Any other suggestions? Does part of the system pass through the firewall into the cab? Could there be a leak in there?
 
What if I can’t find an AC leak even with the Mastercool Professional UV Detector Kit? I was low on refrigerant according to the gauge. I added some, cranked the Jeep on max air. Finally got pretty cold air. Within a week it will be warm again. So after recharging I added some of the UV dye and ran the Jeep and max ac for 10-15 min. Can’t find anything with my UV light. I thought maybe it’s a slow enough leak that it won’t show up for a few days. Thought I’d keep running and checking it. Any other suggestions? Does part of the system pass through the firewall into the cab? Could there be a leak in there?

Unfortunately the dye is not a100% test for leaks. One of the more productive tools is the refrigerant sniffer that can even detect a core leak by inserting the wand into the closest duct. I was pulling my hair out trying to locate a leak until I discovered the low pressure switch had an internal leak that did not show dye but was picked up by the sniffer. Another trick with the UV light is to run the system up to temps then thoroughly inspect everything including the condenser coil in a dark garage, then look for any hint of dye in the condensate puddle on the floor as the evap coil condensate can pick up the dye.
 
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What if I can’t find an AC leak even with the Mastercool Professional UV Detector Kit? I was low on refrigerant according to the gauge. I added some, cranked the Jeep on max air. Finally got pretty cold air. Within a week it will be warm again. So after recharging I added some of the UV dye and ran the Jeep and max ac for 10-15 min. Can’t find anything with my UV light. I thought maybe it’s a slow enough leak that it won’t show up for a few days. Thought I’d keep running and checking it. Any other suggestions? Does part of the system pass through the firewall into the cab? Could there be a leak in there?

I to have a leak somewhere I can't detect. Expecting the leak is at the evaporator because I can't detect it with the dye.
 
To answer your questionYou could have a leak inside the cab in the evaporator. It would have to be a crack or very small hole, maybe from rubbing or something. The connections to the evaporator lines are on the engine side of the firewall. As TJ4Jim said dye is not always a cure all. Used a lot in the automotive field though, and on the whole fairly successfully. I used nitrogen on the farm equipment a/c systems, and that is what we use at work. I realize that not everyone will have a nitrogen bottle in their garage. And I also realize that at $100.00 plus shop rate per hour, one might be reluctant to visit a repair shop. One of the things I like about nitrogen is you can crank up the pressure, shut the valves and see if it will hold, if not using snoop or soapy water you then start looking for bubbles, often with a mirror on the under side of fittings or solder joints. In theory you should be able to do the same with dye, but not always in practice. We hired some very good automotive techs a few years back and they were skeptical of nitrogen, never heard of it. Now it is all they use. If all else fails I would recommend finding a good a/c shop that uses it.

B
 
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To answer your questionYou could have a leak inside the cab in the evaporator. It would have to be a crack or very small hole, maybe from rubbing or something. The connections to the evaporator lines are on the engine side of the firewall. As TJ4Jim said dye is not always a cure all. Used a lot in the automotive field though, and on the whole fairly successfully. I used nitrogen on the farm equipment a/c systems, and that is what we use at work. I realize that not everyone will have a nitrogen bottle in their garage. And I also realize that at $100.00 plus shop rate per hour, one might be reluctant to visit a repair shop. One of the things I like about nitrogen is you can crank up the pressure, shut the valves and see if it will hold, if not using snoop or soapy water you then start looking for bubbles, often with a mirror on the under side of fittings or solder joints. In theory you should be able to do the same with dye, but not always in practice. We hired some very good automotive techs a few years back and they were skeptical of nitrogen, never heard of it. Now it is all they use. If all else fails I would recommend finding a good a/c shop that uses it.

B

All good info and nitro was always our go to method.
 
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