Recharging A/C



The air conditioner in my 96 Tahoe is blowing warm air. I bought a cannister of R-134a refrigerant (+ sealer) with an attached pressure gauge, but I’m not sure which port to use on the A/C system (the instructions it comes with are a bit vague). There are two lines with ports running from the compressor. One leads to a large cyclinder at the back of the engine compartment, the other to the bottom front. Which is the correct port?


Before you hurt yourself, return the refrigerant to the place from which you bought it, then take your vehicle to an automotive AC specialist and let them fix it. They have the necessary equipment and expertise to do the job correctly. You and I do not.


The service ports are 2 different sizes and the line you need should be the one from the compressor to the accumulator, or the canister as you call it.

I would agree that you might be better off geting someone to look at this. Blowing warm air may mean low or no refrigerant charge or not.
If the system is empty then ask yourself where it went. It leaked out and that’s exactly what will happen with the refrigerant you’re planning on putting it.


With the power on, carefully feel the pipes. The suction line will feel cold and the liquid line warm. The suction line is also larger than the liquid line and should have insulation on it.

I do not recommend “Super Seal” and similar leak stoppers. They can cause more problems. Use some A/C UV dye (make sure it’s compatible with polyol ester oil) to find the leak and fix the leak correctly.


On my cars and trucks there hasn’t been a choice - only one of the ports fit the charger. The process was safe and easy for me. My experience with the stop-leak type refill is that it only stops the leak for the duration of the summer and over the winter the refrigerant leaks out again. Weight the cost of refills with the cost of getting your AC repaired.


you want to add to the low side which is bigger line than the high side .high side line is smaller but fitting is bigger.if you bought a r 134 a charger from the parts store it will only go on the low side any ways will not fit on the high side


Both fittings are 1/4" flares. A standard ACR hose will fit on either fitting. However, the hoses are color coded (or should be!) so the blue hose should go to the low side, which is cold. The red hose should go to the high side, which is warm or hot. The yellow hose is used for charging, recovery, and evacuation.


Ignore the last post before this one. The vehicle fittings are not 1/4" flares and the hoses will not interchange. Lord.


Yeah… star is at it again. What the heck is he talking about?


As usual, he’s talking about stationary HVAC/refrigeration units, nothing to do with automotive AC.


Those Egyptian hieroglyphics make more sense; at least you know they’re based on fact.