How do you recharge ac on 1998 Pontiac transport?

Answer 1

You read the chart that is attached to the under side of the hood, and determine which type of freon is in your system. It took me a while to find it on my 1998 Trans Sport, but the refrigerant is R134a. There are actually regulations in force that prevent the do it yourselfer from working on their own A/C. This is in order to keep from accidentally adding more ozone robbing gas to the atmosphere.

They sell a kit at Advance Auto Parts for about 20 bucks that has ~18 ounces of R134a plus oil (needed to keep gaskets lubricated) and leak sealant, as well as a flexible hose with a pressure gauge on it. You can probably buy the same thing at just about any auto parts store.

You attach the A/C recharging container, valve and hose assembly to the low pressure part of the A/C system recharge valve located down below by the manifold on the side of the engine, and next to the radiator. On my 1998 Trans Sport, I found this JUST behind the radiator, in front of the engine. There are two aluminum looking pipes down there, the larger one has a valve with a black plastic cap on it, and the cap just screws off. That's the one you are looking for. Be VERY CAREFUL recharging the A/C on the Trans Sport, as the cooling fans for the radiator are running in the same area that you are working in!!! (Don't get your fingers or anything else chopped off.) The A/C compressor must be running while you are adding the freon, and you will hear the freon flowing into the line which is the suction or low pressure side of the system. The valve has a plastic cap on it, and after you remove that cap, you can hook up the recharging hose. The freon will flow into this line, and because the compressor is sucking the freon out of the container it continues until the can is empty. Use a thermometer stuck in the center air grille in the dash of the vehicle. The objective is to get the air temperature down to about 40 degrees Fahrenheit. I didn't use a thermometer to measure the air. The recharge kit I bought had a gauge on it that was color coded. I don't remember the entire color scheme, but I do remember that the directions wanted the pressure to be in the "blue" area on the gauge. After I'd emptied the whole can of refrigerant, the pressure was showing in the blue area. And, my A/C was cold again!

Don't add more that two cans of freon to the system.