PontiacBonnevilleClub.com

Hi,
I bought a recharge kit from Walmart and tried to add refrigerant to the system.
The system was recharged at the mechanic a month ago since it was completely empty. They checked for leaks and one of the hoses was leaking. The cost of repair seemed too high so a month later I decided to see how much of the refrigerant has leaked and to add a Seal leak and a refrigerant if needed.

First I checked the pressure and it was lower than normal so I tried to add a seal leak first.

After the can was emptied , the pressure reading did not change all. I thought that was because the seal leak had only 2 oz of the staff . So with the hose still connected to the Low Pressure gauge, I unscrewed the Seal Leak can and screwed in the R134 can and started charging. I was checking the pressure every 30 seconds while adding the refrigerant and the pressure was always the same. After the can was empty , the pressure reading was the same as before.

Now I am reading the instructions again and I see two things that I did wrong.

1. The instructions say to first connect the can of coolant to the hose and then put the hose on the low pressure gauge.
I did in different order. Since I first was checking the pressure, I didn't take the hose off the Low Pressure gauge and just attached the can.

2. Some instructions I read online say that after screwing in the can I have to turn it a little back so it would release the refrigerant (?) and then screw it tightly.

My questions:
1. Since I connected the hose to the Low pressure gauge before I attached the R134 can - I might've put some air from the hose into the system. Is it so? How bad is it? The A/C worked fine afterwards.

2. Why didn't the pressure change? Can it be that connecting the hose in wrong order would prevent the refrigerant from entering the system? Where did it go then?

3. Is it possible I didn't attach the hose to the Low pressure gauge properly? First I was having trouble connecting it, but eventually it snapped. And I was able to read the pressure.

4. Is it possible the hose is faulty? I doubt it since it shows the pressure.

I am thinking about checking the pressure when the temperature is colder. I was recharging it when it was 85 degrees in the shade, so maybe I check the pressure when it is 65 degrees in the morning and see if it stays the same as before. That would suggest than the hose is faulty.

Any suggestions?

Thanks.

I don't have answers to all your questions but, that leak seal stuff will clog the orifice tube. It's also possible that your leak only holds a certain amount of pressure. If you add more, it could just be leaking out.

You should really get a good set of gauges to see what the high and low side are doing.

What pressure was it at when youu were doing all of this?

RJolly87 wrote:What pressure was it at when youu were doing all of this?

Around 33 psi.

You really need a gauge manifold to do any diagnostic with A/C.
My recollection is that once I had the system filled with enough refrigerant that the compressor would kick on, and the vehicle was running, adding refrigerant wouldn't effect the low side pressure once it stopped short-cycling. The low side stayed pretty stable while the high side increased with added refrigerant. The system can be overfilled with a low pressure reading in the 'green' if the high side pressure is too high. The actual pressure value is dependent on temperature, humidity, so it's difficult to nail down a specific correct pressure, and impossible to do without a manifold as you need to be able to see both high and low to charge the system. 25-40psi is normal for the low side while operating.

MattStrike wrote:You really need a gauge manifold to do any diagnostic with A/C.
My recollection is that once I had the system filled with enough refrigerant that the compressor would kick on, and the vehicle was running, adding refrigerant wouldn't effect the low side pressure once it stopped short-cycling. The low side stayed pretty stable while the high side increased with added refrigerant. The system can be overfilled with a low pressure reading in the 'green' if the high side pressure is too high. The actual pressure value is dependent on temperature, humidity, so it's difficult to nail down a specific correct pressure, and impossible to do without a manifold as you need to be able to see both high and low to charge the system. 25-40psi is normal for the low side while operating.

Absolutely true about the gauges. The 02 Bonneville also has a variable displacement compressor, which is also part of the reason you observed what you did. It will typically show cooling issues before there is a large impact on pressures. Even with a full gauge set, it's hard to see the difference between a low charge and a full charge, despite one side being luke warm. It's usually pretty good at keeping pressures where they need to be, despite the amount of refridgerant that is or isn't in the system.

The big concerns with air in the system are that it doesn't have the same phase change properties as the refridgerant, and it also carries moisture. If too much moisture enters the system you will have problems, which, again, can be dangerous if you are only looking at low side pressure, because you would only see the low side half that keeps dropping pressure, but wouldn't be able to see the high side half that keeps spiking pressure.

Also keep in mind that the pressure will likely be inherently different at different temperatures and humidity levels also, as mentioned.

Also, always act with safety in mind. You are dealing with a system that, even at rest, is packing a liquid at 75-200+psi, that can freeze on contact, and is flammable (even explosive) under the right conditions. All it takes is one wrong move to change your life.

Sorry for the soapbox, but I see too many people eager to grab a can and stick it in. I was one of them, until I made one wrong move, and was thankful that I was not in the path of a 12 foot tall fountain of frostbite pain when it went off, and it wasn't even running when that happened.

The first thing you did wrong was to not repair the leak.
The second mistake was using ac stopleak.
As others mentioned, it can easily clog things up rather than just stopping leaks.
A proper ac service (and a way to detect leaks) includes vacuuming the system down.
Vacuuming down a system removes moisture from the ac system but there are also are a couple of parts that must be replaced whenever you open the ac system up--the orifice tube and the accumulator (also called a receiver/drier).
The orifice tube traps debris and the accumulator traps moisture which can otherwise cause acids to form that damage the ac system and can cause ice blockages inside the ac system, too.

The best time for a home mechanic to fix a leaking ac component is when the ac system is already empty, since you won't need a shop to empty it for you.
(Discharging refrigerants into the air is illegal.).
As for the hose needing to be replaced--maybe it was the hose itself or maybe it was the far cheaper ac o rings that are on every place there's a connection or even just a faulty schrader valve.

Here's just about everything you need to learn about ac troubleshooting and recharging:
http://www.aa1car.com/library/ac98.htm
http://www.aa1car.com/library/ac_recharging.htm
http://www.aa1car.com/library/macs_serv ... edures.pdf

A/C is one of those systems that requires the right training and tools to properly service and maintain. Many years back I had invested time and money in both some basic training and the proper tools to work on automotive air conditioning systems. Not to sound harsh, but your cost to fix this problem may have just become more expensive than if you had it fixed properly the first time. If you have a leak you'll be recharging it endlessly and as already mentioned, adding a stop leak agent to A/C systems is potentially very counter-productive. Most backyard DIYer's shouldn't be touching this and the crap they sell off the shelves at department and auto part stores really should be illegal (IMO).

Seriously, take it to a professional shop before you throw more money at this.

ddalder wrote:A/C is one of those systems that requires the right training and tools to properly service and maintain. Many years back I had invested time and money in both some basic training and the proper tools to work on automotive air conditioning systems. Not to sound harsh, but your cost to fix this problem may have just become more expensive than if you had it fixed properly the first time. If you have a leak you'll be recharging it endlessly and as already mentioned, adding a stop leak agent to A/C systems is potentially very counter-productive. Most backyard DIYer's shouldn't be touching this and the crap they sell off the shelves at department and auto part stores really should be illegal (IMO).

Seriously, take it to a professional shop before you throw more money at this.

The cost of repair I was given was $350-$400.
I have to find out first how long will the charge hold. Then I will decide what is the most cost effective way to deal with it. If I am able to drive whole summer with a charge that cost $30 - that will make much more sense in my case since the car is 16 years old and I doubt it survives another 10 years.

Anyway,
I measured the pressure this morning when the temperature was 70 degress. The reading was 32 psi. Which is within normal for the temperature although on the low side. The pressure was 35 psi when it was 85 degrees two days ago and that was lower than it should be for that temperature. Kind of strange.

hi, in the future, to check pressure, turn the wingnut all the way closed on the can and no juice will come out and you will get the system pressure with ac clutch off or on. always disconnect from low port to change change cans but dont turn wingnut to puncture can until you connect to port