A/C leaks

[Eneto-55]

2010 Dodge Grand Caravan. 

I have never needed to add refrigerant before, but this Spring it was HOT in there.  Added a can, and it was cold again, but not for long.  Maybe a week at most.  This vehicle has the rear A/C controls, and I assume that it also has a second condenser back there too, although not sure of that.

Years ago I saw the refrigerant that includes dye, and I tried it out, but I apparently didn't read the part about needing a UV light to see the dye, so never saw anything, and didn't find the leak.  I had already had some bad experiences with re-built A/C systems shelling out again pretty soon after the bill was paid, so that one I just drove it w/o A/C, like it was in the old days. (Except that modern cars are not built to drive with the windows down, so they are noisier than the ones from when A/C was still a luxury.)

 

So, the question:

How do you all go about finding a severe leak like this?  I just watched a video this morning where a guy ran compressed air into the A/C system, then listened for the leak.  (He had a headset and a microphone on a wand, so he could stick it down into hard to reach areas.)  He just threaded an air chuck male connector onto his A/C gauge set, which, as he said, is not the same thread count, so he just had it on one or two turns, then wrapped a wide rubber band around the fitting area to reduce the air leak at that point.  Gave me the idea of using an empty refrigerant can.  I was about to use a drill to make a hole in the bottom when I thought about how much damage one little spec of steel could do, once it got into the compressor, so I used a punch.  Started with a small one, then worked up to one that made a hole large enough to thread in the air coupler. That works fine for the low pressure requirements for this test.

 

BUT, would you do it?  I'm hesitant, because I've never heard of this idea before.

[Plymouthy Adams]

a halogen sniffer is very inexpensive.....

[Plymouthy Adams]

as an aside, check carefully about the main gasketing areas, compressor low/high ports, the relief valve, the receiver dryer, condenser and the connectors at both evaporators given you have rear air.  Check also for a leaking trinary switch.  

 

To check the evaporator you probe the ducts nearest the evaporator you can get.  AC with some charge, operate, turn off let stand (no air movement) listen for detection.

[kencombs]

I have a 2007 T&C which had a leak, thankfully way back when it was in warranty.   Rear evaporator.   They had a bunch of them due to a run of bad ones that cracked.  Probably not your issue though being older as they usually failed early.

 

Sniffer is the easiest way.   OTOH, with refrigerant leaving that quickly I'd expect to see dampness from oil at the leak point. So I'd first follow every visible line, check every fitting for that.   If no luck with that a detector can be had for less than 35 bucks.   But, I can't vouch for the accuracy of the really cheap ones.

[greg g]

There was a recall on those.  I remember there being steady work for 2 techs at the dealership 

I worked at.  Some engineer decided that it was a good idea to put aluminum tubes and fittings and attaching them to steal subframw components.  He must have missed the lessons on galvanic corrosion in damp environments. Throw in a couple winters driving on salted roads, and you have hundreds of thousands of Van's being recalled.  The techs loved them.  Chrysler paid 2,75 hours for the repair.  The guys got it down to about 40 minutes. Hey could do 6 or 8 a day if the parts guys kept a proper stock pile of the repair assemblies.

[Sniper]

I don't see any pressure readings.

 

You don't know that you have a leak, all you do know is that you do not have a working AC system.  Many things can cause that.

 

[Dave72dt]

UV pen lights can be had for not a lot of money. If you need to have your system professionally recharged and that can of UV dye freon also had Stop leak in it, tell them before they start running their equipment.  The Stop leak messes up their equipment filters and they won't be happy

 

I'll assume you used a DIY kit to load the freon.  Some of the better kits come with a gauge on them and would recommend them over the no gauge units unless you have the full set of stand alone.

[Eneto-55]

On 8/6/2023 at 9:30 AM, Sniper said:

I don't see any pressure readings.

 

You don't know that you have a leak, all you do know is that you do not have a working AC system.  Many things can cause that.

 

I assume that it is a sever leak because I put one can of refrigerant into the system, and it was very cold again.  And then within a week it was no longer cold. 

 

I do not have the A/C service setup that has gauges for the high and low pressure sides.  I only have the filler hose.  I do also have a pressure gauge, but when the A/C got cold, I didn't bother checking the reading.  If I felt like wasting another can of refrigerant, I could fill it again, and then take a reading for the low pressure side.  I did purchase another can, and also a can of stop leak, one that contains a bit of refrigerant, just enough so that it will load it into the system.  But then I saw the video I mentioned, and thought that if I could safely find the leak, that would be the approach to take: identify the leak, then take it into a shop for repairs.

Edited August 7, 2023 by Eneto-55
spelling error

[Eneto-55]

2 hours ago, Dave72dt said:

UV pen lights can be had for not a lot of money. If you need to have your system professionally recharged and that can of UV dye freon also had Stop leak in it, tell them before they start running their equipment.  The Stop leak messes up their equipment filters and they won't be happy

 

I'll assume you used a DIY kit to load the freon.  Some of the better kits come with a gauge on them and would recommend them over the no gauge units unless you have the full set of stand alone.

Yeah, just the hose deal.  Thanks for the warning about the stop leak in relation to taking it in to a shop, or attaching gauges.  That's logical, but it hadn't occurred to me.

[Eneto-55]

I posted this question on the MoPar minivan fan site as well, and got a fair bit of "push-back" about putting shop air into an A/C system.  (This was one of my misgivings, so I was glad for the input on that, confirming my reluctance.)

One guy really didn't think my "air chuck fitting threaded into the refrigerant can" deal would hold much air at all, so I did a test.  Secured the hose and the can (so nothing would get wild in case it really DID come apart), and slowly ran the pressure up.  Stopped at a steady 50 PSI (with no escaping air).  As I commented over there, I do not plan to put shop air into the system, but might do further testing on that can, just for anyhow, as they say where I come from. But I'll look for some sort of cage to do it in, so if/when it comes apart, it won't be anything but a laugh - no personal or property damage involved.  (This from a guy who, as a young person, connected a large capacitor to an electrical cord and flipped the breaker on - from across the shop.  Nice BANG, and paper & thin foil wrapping flying all over the place....)

[Sniper]

the problem with using shop air is that it contains moisture, that will freeze up inside a working AC system.  Which is why AC systems have desiccant in there, to trap any residual moisture.  Shop air will overwhelm that, even if your have a moisture trap on your air line.

 

Use nitrogen of you have it.