Well its been another winter here in Manitoba. Lots of really low temps, mixed in with lots of warmer weather. Similar to 2009, when I had the same problem. When it warms up outside, I can hear a hiss coming from my expansion valve under the dash. Last time, I brought it to a local shop and it ended up being about $400 to replace the low pressure AC pipe (runs along the firewall). I hate that they make these pipes out of aluminum, they are quite prone to cracking, especially at the tees.

Anyways, being in a similar situation, and not too excited to shell out $400+ again, I was wondering if anyone out there has ever just recharged their AC themselves? In Canada its pretty difficult, you can't even buy R134a without a license. There is this Duracool or RedTek stuff, which I have heard is just refined propane. But you have to totally purge your system, and the jury is out if the stuff even works well.

Last time I was in Fargo (about 4 hours south of here) at Target, I recall seeing R134a in 6oz cans for about $8. So is it really as simple as shelling out the $8 + buying the tool with a gauge to see if the charge will hold? My theories behind this strategy are:

1. The constant temperature changes caused the refrigerant to leak out. So no real leak, and maybe I just need to top off after long periods of extreme cold.

2. I have a slow leak, and maybe a can or 2 will keep me going for the summer or longer. Still cheaper than taking it in.

One thing that scares the hell out of me is the reports on here about rear AC and water lines corroding and leaking. From what I gather, unless you are really lucky, these are pretty much impossible to fix without lifting the body off the frame of the truck. Seeing how they run AC lines at work, I would be tempted to fab up my own copper or rubber lines and snake through the frame versus repairing these. Hopefully my leak is not back there. I've visually inspected what I can, and checked the rubber grommets holding the pipes, and there does not appear to be any issue.

Anyone have any thoughts to my problem?

Recharging your A/C system is fairly easy. You can buy R134 at almost every auto parts store here in the states and even walmart. The biggest thing to make sure is that you have a guage when you fill. A/C system is very picky on the amount you need. If you under fill, there is not enough coolant to cool the air. If you overfill, there is not enough room for expansion and cooling of the air as well. You will only be able to fill from one side, to be honest I don't remember if it's the high or low side of the a/c system, but I do know for sure it's the smaller of the two valves. You have the car turn on, run the a/c on high with full blower attach the hose with guage is best in my mind, that way you never overfill and open the can. Tilt from 12 oclock position to 6 oclock position until the can empties or you are in your desired range. after you tilt the can down the needle will spike but then settle. Let it sit for a sec before tilting again to make sure it settles unless you know you are empty, keep going. I hope this helps. If you have other questions, let me know.

you could do it, but if you don't vaccum check for leaks and add some dye....you may just be venting the stuff you just bought into the atmosphere. If it happens to be leaking into your interior through your evaporator or something, wont be the best thing for your health either.

If it's not as cool as you remember, one of those kits might do, but if its so low the compressor isn't engaging (and its not some other issue) - you definately have a leak.

Here in the US you can buy the 12 oz or larger cans of R134a, but the store will also have a can that has some “stop leak” included with the Freon. There are o-rings & gaskets that are “renewed” with the formula. So get a can of that for sure & follow directions.

The label around the radiator will give the amount of refrigerant the system holds.
Are you sure it all leaked out? If so, the “low pressure” switch will not allow the compressor to engage. It’s not good for a compressor to run with without Freon.
To properly fill a system, there are 2 methods (both require dual pressure gauges):
Evacuate system to a given psi to remove all Freon & impurities such as moisture;
Add Freon until appropriate pressures are obtained per the ambient outside temps.

As for how to hold the can while filling system… Keep in mind that the pump is called a “compressor”. It is designed to compress a gas, whereas a liquid refrigerant dump can easily damage the piston & valves (Similar reaction when water is sucked into the engine when crossing a river)

be carefull....if you add impurities (like stop leak or whatever), you may have issues later if you try to recharge or repair with an ACR5 or later machine. It always samples first and won't evac contaminated refrigerant. Having the system under vaccum also boils off the moisture in the system, which is good.

I guess if the can is cheap enough it might work, especially if you can get a 12oz can.....you could do it once a year for the next 7 years! Also watch for the ester/pag (greenish) oil seeping out from the lines (usually low press) at the crimps. If you lose enough of that, your compressor wont be happy either. I wouldn't recommend guage charging for anyone without some experience, temperature/humidity/etc have an effect.

My personal opinion would be get it UV-light checked - if nothing shows, evac, recharge with the proper charge, oil and dye.....unless it's a huge leak, should at least be good for summer.....

[quote="Tech"]be carefull....if you add impurities (like stop leak or whatever), you may have issues later if you try to recharge or repair with an ACR5 or later machine. It always samples first and won't evac contaminated refrigerant. Having the system under vaccum also boils off the moisture in the system, which is good.
quote]

Thanks for the warning. Took a class on home HVAC, but automotive and its differences were not discussed.

no prob! the older machines dont sample, so any mixed refrigerants or whatever get recovered and pumped back into subsequent cars.

To avoid this, newer machines now sample the gases first, and have and internal scale thats more accurate. Other than that, the stuffs pretty much the same as standard HVAC, with smaller charges.

Agreed with the adding of stop leak etc. It's better just to fix the problem correctly, by replacing the seal/valve etc then trying to just cover it up. You end up doing the work again if you just use a temp fix like stop leak.

So we went to Grand Forks this weekend for Mother's day. I picked up an 18oz can of R134a that included a hose/gauge assembly for $23. Ambient temperature was about 60F, so I had to use the table on the side of the can to figure out the correction factor for the correct PSI.

The manual says the system takes about 30oz in total of refrigerant. I used almost the full can of 18oz. Process took about 5 minutes, and the AC is working great. Will test the pressure after a week or so to see if I am losing pressure or not.

Last time I had a leak, because of the laws up here in Canada, I had to take to the shop. You can't buy R134a from the store here, you need a license. That bill was $400, and I really highly doubt that what they charged me for actually fixed the problem. More likely, a recharge similar to what I did this weekend would have probably fixed my issue for the 2 years.

Nice! Glad you got your A/C working again. It only took a trip to the US, sounds like Canada needs to get rid of that license law so you can buy and use at at a store. Not sure what that cost in gas, but nice to be able to do it yourself.

volvite wrote:Nice! Glad you got your A/C working again. It only took a trip to the US, sounds like Canada needs to get rid of that license law so you can buy and use at at a store. Not sure what that cost in gas, but nice to be able to do it yourself.

Fortunately we were going there anyways, so no real cost in fuel. But even if I did a special trip, I would only be into the repair for $125, so still far cheaper than doing it up here in the great white north.

t

Yeah I found out how to do this last year when my wife AC went out on her Stratus. Get the guage and check the high and low sides while its running to make sure it's close to specs so you don't have anything big wrong, compressor, condensor or leak, and you should be good to go. I buy a can each year and adjust both of ours just to make sure its work at full capacity.

disallow wrote:

volvite wrote:Nice! Glad you got your A/C working again. It only took a trip to the US, sounds like Canada needs to get rid of that license law so you can buy and use at at a store. Not sure what that cost in gas, but nice to be able to do it yourself.

Fortunately we were going there anyways, so no real cost in fuel. But even if I did a special trip, I would only be into the repair for $125, so still far cheaper than doing it up here in the great white north.

t

Nice. So it worked out for the best.

I’m feeling your pain! Yesterday we had a day in the 80’s, so it was time to try out the A/C. It wasn’t warm but sure not cold air coming out the vents. Last summer it took a can and looks like a repeat performance for this year. I guess it’s an age related issue. Good thing I stock up when it’s on sale.

Well, age in the sense that older stuff is more likely to leak. My Pathfinder had a tiny leak at the drier in the front by the radiator. Would have never found it myself but Nissan went over the whole thing with a fine toothed comb when they couldn't find why it was switching on and off (eventually found the radiator was partially plugged and very slightly overheating the engine).

If you need a can once a year you have a leak somewhere. Autozone and others sell a kit for looking for leaks with U/V dye if you're adventurous.

Slightly off topic but maybe ten years ago I had an A/C plant (big water chillers) on a ship that everyone swore didn't work well in that class. Mine worked fine, alone on the waterfront...the difference was I had a couple A/C technicians who were really aggressive at looking for refrigerant leaks and fixing them so things didn't snowball. In general I think A/C is very susceptible to death by a thousand cuts, and Pathfinders unfortunately have lots and lots of tubing and junctions compared to smaller vehicles...