Air Conditioning Help

Hi,

I have a 2001 Pontiac Grand Prix GT and I just went to the local shop to have my ac charged. Well, a week later the system is blowing warm again. Obviously I have a leak somewhere. I wanted to pump some dye into the system to determine the leak but my question is how many cans of 134a (w/dye) should I pump into the system? I have a pressure kit but want to ensure I do not put too much/too little into the system. What is the proper pressure range? Do I put enough to charge the whole system back? I just don't want to pay another $100 bucks for the shop to pump $20.00 worth of dye into the system.

Thx

compressor shaft seal is number one leak location, compressor belly is number two....

What are the proper specs? How much freon/oil do I put into the system? Do I fully recharge the system or should I just put a couple pounds freon dye into the system?

On a total system evacuation you should use 2.25 lbs of R134a refrigerant. Double check the data label located under the hood. It varies with the PAG 150 oil and what A/C component is removed or replaced. You can get PAG 150 oil with dye in it.

The most important part is rent a electric vacuum pump before recharging the system and pull vacuum on the system to 27-28 hg for at least 30 or up to 60 minutes.

When I repaired refrigerated waterbaths. After replacing the bad parts, I would pull the system down to the lowest vacuum I could get. Close the system off and leave it over night. Then check it the next day, and if the vacuum dropped I would check all the brazing that I did to make sure that I did a good job, if not I would re-braze the bad weld that I did.

I bought a vaccum pump and gauges and I'm ready to go. When I evacuate the system via the vaccum pump, does that also purge all of the pag oil from the system?

No, the oil does not come out of the system when pulling a vacuum.

I just found out that my ac pump is bad. Go figure. When I replace the compressor do I buy pag oil in the air compressed can and or in a regular screw top bottle? As well, what grade of pag oil do I buy (46/100/150?) Thx

If you're buying a new or reman compressor, you need to buy the pour-in PAG-150 oil. The oil needs to be added to the compressor itself, then the compressor needs to be hand rotated 10-15 revolutions (read the instructions that come with the replacement compressor for suggested amt) to distribute the oil prior to hooking it up. Failure to do so will result in compressor failure.

I just found out that my ac pump is bad. Go figure. When I replace the compressor do I buy pag oil in the air compressed can and or in a regular screw top bottle? As well, what grade of pag oil do I buy (46/100/150?) Thx

If you haven't lost any oil from your system, you're supposed to carefully remove the old compressor and pour out and capture the oil that is in it. You determine how much oil this is and then put that exact same amount of fresh oil into the new compressor. If you've lost oil through a leak, all bets are off.