AC Blowing Warm Air

[brewster812]

Newbie here. I have a 1993 Explorer with 110,000 miles. I only drive it once or twice a month. Now that it has gotten hot in Maryland, I turned the AC on and it would only blow warm air. Last summer it cranked out the cold air, and I don't remember the air being warm this spring but it wasn't very hot outside back then. I haven't had any problems in the past with coolant leaks. I really don't want to spend the money to take it to a shop. Any idea what the problem may be? Thanks for your help.

 

[arco777]

Eventually all systems get old and leak.

Is your system converted to R-134 is it R-12?

Is your AC compressor cycling on and off while the AC is turned on? If so, it is low on freon. If it's R-134, check if the system is completely depleted - carefully poke the shrader valve on high or low side fittings (shield your eyes!) and see if there's pressure. If there is, then you can buy a can of freon and a cheap recharge kit at any parts store and recharge it yourself. Follow the directions carefully and don't over-charge the system.

If there's no pressure at either fitting, your system is completely empty and you need to have it evacuated and put under vacuum before charging it. A shop will be able to do this.

The severity of your leak will vary. It may be something you only have to charge once a year at this point (though it may gradually get worse), or if it is more severe, it may be cheaper to find the bad seal and replace it before recharging the system. You can use refrigerant with UV dye added to help find the leak.

 

[runningred92]

The severity of your leak will vary. It may be something you only have to charge once a year at this point (though it may gradually get worse), or if it is more severe, it may be cheaper to find the bad seal and replace it before recharging the system. You can use refrigerant with UV dye added to help find the leak.

If your system has been swapped over from R-12 to R143-a by way of the cheap swap then you probably can just recharge the system. The problem with that type of swap is the actual R134-a particles are actually smaller than the R-12 particles and escape through multiple spots in the system. But like Arco777 said you may have a more severe problem that will need to be fixed. Mine had the cheap swap done before I bought it so I have to recharge the system only once a year and it works just fine. I am ok paying $20 every summer to stay cold.

 

[brewster812]

As far as I know the system has not been converted to R-12. Does that effect how I diagnose the problem? How would I know if it had been converted? Thanks for the responses!

 

[safn1949]

The problem is R 12 is real expensive,you don't want to go there.I have to put about $25 worth of R 134A in mine a year,I have never been able to pinpoint the leak.

 

[arco777]

1994 Explorers had R-134 but I'm not sure about 93. Check on your heater box for a specification sticker. Also you can check your compressor, it may be marked.

You need to know whether you have R-12 or R-134. R-134 is newer and available everywhere. R-12 is no longer legal for sale to the public and is hard to find but supplies do still exist. R-12 molecules are larger than R-134 and it cools a bit better than R-134.

You can't mix R-12 and R-134 in a system. R-12 seals will not hold in R-134 and will leak it out quickly.

If there was ever a retrofit from R-12 to R-134 you may see stickers evidencing it. But if your factory stickers indicate it always had R-134, no sweat.

A proper R-134 retrofit or a factory R-134 system will have all R-134 specific seals.

If you have R-134, fixing a leak or topping up the system is as simple as charging it yourself with a DIY kit or having a shop do it; to fix a leak you need to pinpoint the source of the leak. You can use UV dye to help find leaks or have a shop pressure test the system. Replace the seal in question and you should be good to go.

If you have R-12 you can replace bad seals with R-134 seals - but, you'd still need to find R-12 to replace the refrigerant in your system. The only alternative is a full retrofit, which involves replacing every seal in the system including the compressor itself. Most of the work involved is best left to a shop if you're not comfortable tearing it all apart, and a shop's necessary to properly charge an empty system anyways.

 

[sirhk100]

Bump since it's on topic...

Mine blew nice and cold on a trip I took 2 weekends ago. 300 miles north, cold the whole way. Parked for 3 days, come home, blowing cool at best the whole way home. Never cold... 104 degrees out and probably blowing maybe 75-80 degrees at the vents. Mine is still R12. Compressor is spinning, things are working. I'm guessing it just lost it's charge. I've seen stuff at the parts store that says it's R12 compatible. Anyone have any experience with this stuff? I figured it can't really hurt to give it a shot. Just curious... If it works but goes away relatively fast maybe I'll look for leaks. Then again, if there's a leak, I've gotta crack the system open and at that point I might as well just pay to have it converted I suppose. (kinda talking out loud here as I type on the fly... LOL) Anyways, thoughts on that R12 compatible stuff you see at like autozone and pepboys?

 

[4x4junkie]

My thought is any time an R-12 system develops problems such as a leak, save the headaches and just convert it to R-134a from the get-go. All the parts of an R-12 system will be old enough it couldn't hurt to replace them anyway (things like hoses, and of course all the O-ring seals are all likely on their last days). The compressor itself should be usable with R-134a if it's been previously run with R-12 (something about having been previously run on R-12 affects the metallurgy of it's parts making it compatible with R-134a whereas a brand-new R-12 compressor would not be). Compressors can be a frequent source for a leak too though, so it probably wouldn't hurt to replace it as well (new ones should all be R-134a-compatible).


As for "R-12 compatible" refrigerants, I have no experience. Seems I recall somewhere they were primarily propane-based, but I can't say for sure (the important thing would be in how well it carries the lubricating oil through the system). If the R-12 leaked out, chances are that stuff will too (especially if the system was working just two weeks ago).

 

[Swampgravy77]

Air issues: I was cleaning out my radiator system and filling my radiator system back up with fluid. I turned my heater adjustment towards the hottest setting and filled the radiator up. And, once that was done I get back in my explorer and turn the console lever to cool and turn the AC on. And, nothing but hot air. Thanks for any options!

 

[sirhk100]

My issue ended up being a leak. I bought...

R134 conversion fittings
UV fluid and glasses/light kit
Large can of R134.

Threaded the conversion fittings on. Pulled out the shrader valve and poured in the UV fluid. Put the valve back in and charged it up with the big can of 134 till it had enough pressure for the compressor to kick in. Drove it for a day or 3 with the a/c on the whole time. It lasted about 3 days till it stopped working again. I then grabbed the light/glasses from the UV kit and found my hoses were leaking. Pulled them out, took them to my local hose/hydraulic shop and they built me a complete new set. Installed the new setup. Took it to my local shop, had them hook it up to the A/C machine to pull a vacuum on it and charge with R134. Been blowing super cold here in Vegas all summer now!!! 3 months without an issue.