20InchBladesOnTheImpala

2001 Impala LS 3.8L with 142,xxx miles.

ac used to work until the compressor started grinding.
removed the compressor and installed a used one just to keep the car running.
after a few weeks of running it i decided to charge the system with freon.
charged it without pulling vacuum (didnt have knowledge on ac)
ac worked fine for about week then it blew hot air
researched and found out i had to pull vacuum so i did.
pulled vacuum for 20 minutes then left it sitting for 45 min to make sure it was holding pressure (30 inches of mercury or psi or -30 or whatever they call it)
45 minutes passed and it was holding fine so i continued to pull vacuum for another hour. recharged freon (3 cans of 12oz)
again ac only worked for about a week.
decided to change out the condenser, the drier, the cycling switch, and the orifice tube.
did the vacuum/charge again and this timeit only took 2 cans, pressure was reading high and 4 days later no more cool air.

anyone have a clue on what i can tackle next? its hot in texas lord knows i need air lol. thanks yal god bless yal.

tech2

maybe you have a leak? Is the system empty right now or low?
what is the system capacity listed in the a/c label in the engine compartment? This is what it should be charged to. Todays system use small charges...so the fill must be accurate.

the filling method you used is not accurate...if you gotta do it that way...weight the cans before and after.

If it was mine, I would have a shop recover the system, if its low...add dye to it, charge it and let yo u run the system all day every day for a week or until it stops working. the system must be on for the dye to circulate.
I hope you replaced all the seals for every part your replaced. You should have performed oil balancing...this is required when changing major ac parts...like the compressor, drier. If the system is low on oil...the compressor will live a short life...die and spread metal into the system for the next compressor.

20InchBladesOnTheImpala

Is it possible that the compressor is the issue even though it's couch is engaging and it's not making any grinding noises? Everything was fine before my old compressor went out. I didn't have leaks. I added dye in my system this time, I will go outside in a bit to flash the blacklight on it. And I'm not sure if it's low or empty. It doesn't blow cold at at so maybe empty? The clutch is engaging so does that mean there's freon in it? Thanks.

tech2

if the clutch is engaging...the system is not empty. If the system is low on refrigerant; the clutch will engage, the pressure may look reasonable or may be low on a gauge but the system will perform poorly..ie not get cold.
If you need to keep adding refrigerant to make it perform...you may have a leak. the first thing you need to confirm...is the system charged to the correct amount.

If its overcharged, the system will flood the evaporator and perform poorly...pressure will be high on both low and high sides.

20InchBladesOnTheImpala

will overcharge damage the evaporator?

20InchBladesOnTheImpala

i dont have a sticker under the hood that tells me how much freon amount is required. is there a website that tells me? thank u.

20InchBladesOnTheImpala

if its over charged, will it still blow cold for a few days?
it blew cold for 4 days, then it started blowing hot air from one day to the next.

oilcanhenry

If I were you, I'd dump the A/C compressor (you might get away with flushing it out) and flush the entire system out to get rid of any metal/other particles. Install new receiver/dryer and rebuilt compressor, fill with PAG oil to factory specs, pull the vacuum down to -30 PSI for at least a half-hour when it's warm out. Fill with correct amount of R-134A refrigerant, soon to be replaced by the new R-1234yf refrigerant/Freon. Like Tech2 said, adding leak detector with the oil would be a good idea too.



BTW, you can buy an A/C vacuum pump cheap at Harbor Freight, but I'd buy the gauges as well, were I you. Best of luck to you and wear gloves and eye protection.

tech2

the yf stands for your f'ed...the cost for this stuff is $100 a pound

was the old compressor bad internally or just a bad compressor clutch?

2.2 lbs is the correct charge amount
this system uses a accumulator not a receiver drier. 60ml of pag oil should be added to the system when the part is replaced. add it through the low side with the system running.

the compressor should have come with oil balancing instructions...hopefully you followed them.

20InchBladesOnTheImpala

the old compressor was making grinding noises.

the one i have now i bought it used at a salvage yard. it makes no noises and the clutch engages. after i changed the condenser, accumulator, cycling switch, and orifice tube i pulled a vacuum and charged it. it only stayed cool for 4 days.

is it possible the compressor is bad even though it shows no signs of being bad? also last night i went and looked in there with a black light and found no traces of uv dye i had added in there with the freon charge.

thanks