Help w/ Recharge A/C on 1996 Subaru Legacy Outback 2.5L

[claire007]

I feel really foolish asking for help on what should be a simple procedure. But, I figure its better to ask than to leak any (more) r134 while trying to recharge my a/c.

 

I bought one of those basic kits from Target with the can and the gauge. However, it does not seem to fit on the port. When I try to get it to attach it just releases some refrigerant from the car. Am I missing something really obvious? There are two blue caps on my car, the port under one does not come close to fitting. The other fits but does not lock on at all.

[EVOthis]

First and most important I do not recommend those "kits" at all fore they only give you a gauge for the low side, theres no way to monitor high side pressure while your charging it...unless of course you have a set of manifold AC gauges...Also if you do decide to use it make sure the cap on the little coupler they give you is screwed all the way out and that your putting the coupler on the low side fitting straight otherwise it will not fully seat...

[ScottG]

I'm in agreement with EVO on this matter....the 'kits' are mostly from China and of dubious quality. Also, as EVO pointed out, there is no way to check the high side of the system with one of these kits.

 

I'm going out on a limb and assume that the reason you're trying to add R-134 to your system is that it is not cooling to the level you expect.

 

Should that be the case & you are determined to use the kit you have purchased, you must make sure that the valve adapter on the kit is the right one for the low side valve(larger diameter tube) near the compressor. R-i34 connectors are similar to air tool connections: there is a knurled section of the connector to pull back on as you force it down o the car's valve opening. If you don't pull that section back, you cannot fit it over the valve. Practice pulling it back a couple of times before trying to attach it.

 

You should have some kind of thermometer to measure the temperature at the vents before you try to add 134 to the system. On cool evening, the system should come down to around 40 to 43 degrees F, 40 if you are lucky. It's pretty much impossible to obtain any lower temperatures since the automatic thermostat will shut the compressor down at about 40 degrees.

 

It's a good idea to begin the whole process by measuring the temperature at the center outlets. If it gets down to 40, the system is already doing its best and adding refrigerant will only burden the system, perhaps even raising the outlet temperature because you are overfilling it. Depending on you kit's gauge, full will be somewhere around 30 PSI on the low side.

 

If you want to get a bit more professional about this project, Harbor Freight sometimes has their manifold AC gauges on sale for around $35. They're Chinese & nothing great, but they'll work well enough for occasional home use.

 

Lots' luck & keep your cool

 

ScottG

[OB99W]

[...] Should that be the case & you are determined to use the kit you have purchased, you must make sure that the valve adapter on the kit is the right one for the low side valve(larger diameter tube) near the compressor.[...]

Just to make it clear...

 

Although the low side tubing is of larger diameter, the low side valve fitting is the smaller of the two. The hose should only be able to couple with the smaller valve fitting (13mm).

 

See http://www.aa1car.com/library/ac_recharging.htm for some further info.

[nipper]

I feel really foolish asking for help on what should be a simple procedure. But, I figure its better to ask than to leak any (more) r134 while trying to recharge my a/c.

 

I bought one of those basic kits from Target with the can and the gauge. However, it does not seem to fit on the port. When I try to get it to attach it just releases some refrigerant from the car. Am I missing something really obvious? There are two blue caps on my car, the port under one does not come close to fitting. The other fits but does not lock on at all.

 

 

If you do not know what you are doing, do not do it. This is one of the few systems on a car that I REALLY recomend going to a professional. Refrigerant doesnt just dissapear, it leaks out due to a bad O ring usually.

 

Refrigerant can easily give you serious frost bite at the very least, or damage you AC system.

 

Like everyone else said, the gauges on those cans are there for decoration. You really need a real gauge set to add refrigerant safely.

 

nipper

[tricked919]

I'm going to play the devil on this one... The 97 that I bought last month had a new condenser put in it and lots of O-rings. It was blowing cold air when I bought it. About a week later it quit. I called the guy who sold it (also a subie mechanic) and he said it checked out fine. I posted a thread on here looking for common AC culprits and someone suggested potentially leaky schrader valves. Sure 'nuff I pulled the cap and the high side valve had tiny little bubbles forming inside the bottom of the valve. I happen to have a schrader tool and I was able to tighten the valve by 1/4 turn. I bought one of those guage-in kits for $30 at Napa and charged it to 45psi. Its been blowing ice cold since. I just hooked it up 2-days ago (at the same outside temp it was when I filled it) and it was still holding about 45psi. Granted, I'm a idiot when it comes to AC and I know that isn't the typical fortune for AC issues, but that kit was the perfect fix for what I needed. So unless I missed something - I wouldn't say those are a waste.

[Olnick]

Congratulations! Sounds like you may have caught the culprit. Let us know down the road if it's still holding.

[claire007]

Thanks so much for the replies. I am going to take a second look again tomorrow and hopefully get some photos up in case someone else has the same problem as me.

[Fairtax4me]

Refrigerant doesnt just dissapear, it leaks out due to a bad O ring usually.

 

On the contrary, R134 can and does quite often "just disappear". Or at least that's how it would seem. R134a molecules are so small that they can actually escape the system through the gaps in the molecular structure of the rubber hoses. This is especially true on R12 systems that have been retro fit for R134. Newer hoses are different material which makes it harder for the refrigerant to escape, but not impossible. but if you looked at a rubber hose on a molecular level it's such a maze it would be similar to a person trying to hike 1000 miles through a rain forest jungle. So the refrigerant disappears very slowly, on the order of about 7 - 10 years for R134 systems. But older R12 systems that have been retro fitted the refrigerant can escape in 1-3 years.

 

Now the chances of an O ring failing, or some other component or seal failing in that time are fairly high. Most AC systems end up having to have some sort of work done in the first few years of service. People often have to recharge the system long before enough refrigerant has "seeped out" to notice the difference.

 

 

I've used the DIY kits before but never the kind with the cheesy pressure gauge. Recharged the system in my mothers 98 Camry with one of those most recently, and have done it several times to friend's cars with good success. They probably don't make the system work 100% as well as it did when it was new, but on a 13 year old (or older) car who the hell really cares? If someone manages to overcharge the system, and it still isn't working properly, then there is another reason the system isn't working.

[Scoobywagon]

Refrigerant does not just up and disappear. If it is not in the system, it went somewhere. Here's how you figure it out.

 

1) Recover any refrigerant in the system.

2) Pull a vacuum on the system.

3) Watch gauges to ensure that system will hold vacuum for AT LEAST 30 minutes. If it does not, then wait to see if the vacuum simply drops to a certain point and stops or goes all the way back to atmospheric. If vac drops to a certain point and holds, odds are you're just boiling water out of the receiver/dryer. In that case, replace the receiver/dryer. If it goes to atmospheric, you've got a leak.

4) Add approximately .5 lbs R134A to the system.

5) Sniff for refrigerant using a halogen gas detector. Start at the high side service port and follow the system all around the hood until you get back to the suction port on the compressor. It is likely that you will get hits at the service ports if you sniff immediately after adding refrigerant, so wait just a minute or so. If you consistently get hits in any location, you've found your leak.

6) Charge system with R134a. While charging, add 2oz refrigerant oil with fluorescent dye.

7) Run system to ensure that it makes cold air.

8) Drive car until A/C does not blow cold.

9) Park car in dark area and search under hood for fluorescent dye. If you find dye, you've found your leak.

 

At this point, the only part of the system you've not been able to inspect, either with the sniffer or visually, is the evaporator core. It is POSSIBLE for the aluminum parts in the system to become so thin that the refrigerant can sort of slip through. If this is happening, then you won't find refrigerant dye and its unlikely that you'd sniff refrigerant because concentrations would be very low.

 

This condition is usually found in older vehicles, sometimes R12 cars that have been converted, sometimes 134A cars that have had leaks. It results from the fact that R134A in contact with moisture becomes corrosive. Over time, it will corrode the aluminum parts from the inside and the thin parts get even thinner. This usually isn't a problem with hose fittings because those fittings are usually made with relatively thick walls. The problem will be observed in the evaporator and condenser cores. It will be more pronounced in the evaporator core owing to the higher pressures there. Replace the evap core and do all of that again.

 

Congratulations, you've serviced your A/C system.

[ericcroll]

Do any of you happen to know how much r134 the system is supposed to hold? I evacuated my system, and then put in two cans of r134, and although it is working, it is not getting as cold as I'm thinking it should (97 OBW)

 

Eric

[Fairtax4me]

There is a service sticker under the hood, usually on top of the header panel, that says what the system is designed to hold.

X.X oz of the approved type of oil, X.X grams of refrigerant.