MattZ28

iTrader: (4)

I recently re-did my A/C. One of the lines was crushed, so I replaced the low pressure lines, drier, and compressor. Put the system on a vacuum for an hour, and recharged it with 3 cans of freon. It blew "cool" for a week or so, then got worse and worse to where it's blowing hot air. I checked the pressures yesterday, and both the low and high are at 145-150psi, and the compressor is kicking on.

Does this mean my compressor is bad? Or can it be the expansion valve? (didn't replace that)

Carter Hays

Does this car have an expansion valve? or orifice tube? There is a difference in troubleshooting the two types. Most gm stuff is the cycling clutch orifice tube type.
Sounds like the compressor ain't sucking and blowing. If the compressor let go little bits of get metal spread everywhere. Pull the compressor see if it works. If it is toast get a new orifice tube and flush the system the best you can there are inline filters you can put on that wil catch some of the junk in there.

When you find the problem the high side pressure in PSI should be about 2.2 to 2.5 times outside air temperature in degrees F. and make sure your fans are working. Good luck you'll fix it.

MattZ28

iTrader: (4)

Fans are working...it has an expansion valve. How do I tell if the compressor works by pulling it? It spins just fine and doesn't make any abnormal noises..

Carter Hays

You can tell by spinning it by hand, feel the suction and discharge ports..suck and blow. Don't pull the compressor yet (unless you already have) until you have made sure all other the components are working.
Read up on exactly how the system works and how to interpret manifold gauge readings e.g. The pressure/temp relationship etc..

Usually the guages not moving means the compressor is shot or not actually compressing. High and low side readings being "equal" can mean an over-charge. Do your gauges move at all when the compressor does its thing?

Man, honestly it is hard to for me to troubleshoot electrical or ac systems over the net. I hope I'm too late and you have already fixed it. Tell us what you find.

MattZ28

iTrader: (4)

*UPDATE*

I started the car, A/C low side was at 150. Turned the A/C on adn it went down to 120...after about 2 mins it slowly crept up to 140. When I revved it, it dropped down to 55-60. When I tapped the expansion valve with a hammer. the pressure bounced down and back up rapidly...

we_todd_did

iTrader: (97)

You probly put on a rebuilt compressor (bad choice)

I work on a/c, you compressor has eqaulized and is no good.

we_todd_did

iTrader: (97)

BTW I can get you a brand new compressor for 175 shipped.

MattZ28

iTrader: (4)

Did you read my last post? The pressure drops when the compressor kicks on.

DrivenWS6

iTrader: (1)

Yeah your compressor is on it way out it seems. It should be pulling the low side down to around 30. Whats your high side? The compressors job is to make a pressure change, so if there isnt a real great pressure difference from your low side to your high side then your compressor isnt working like it should.

By the way, you didnt turn the cans upside down when you were charging it did you? Because when you turn the can upside down it charges the system with liquid freon and if any of that would reach the compressor while its still liquid it would tear your compressor up almost instantly. And like stated above if your compressor came apart it spread crap all throughout your system and you will need a new accumulator, FOT and will need to flush the system out the best you can.

MattZ28

iTrader: (4)

I let some pressure out...initially, a lot of air came out, then foamy oil crap. Pressure drops down to 45-50 now when I rev it. I held it at 3k in the car and the A/C got kinda cool, but not cold. (better though, especially for sitting in the driveway in the heat).

Also, I can feel hot air blowing out into the engine bay from around the expansion valve. Is this normal?

DrivenWS6

iTrader: (1)

How do your lines feel? Is the accumulator and suction line getting cool? I guess you could possibly have a TXV stuck open or closed. But you shouldnt have to rev it to 3k to get it to cool at all. It should pull it down to about 30degreees below outside air temp atleast. At idle on a about a 90 degree day mine will pull it down to right around 40 and cruising its prolly about 35 or so.

MattZ28

iTrader: (4)

The low pressure line isn't really cool, but isn't hot either.

DrivenWS6

iTrader: (1)

The low pressure line should be cool to touch. It its a pretty hot day out it should be sweating too. So if its not Im going to have to say its either your compressor or TXV. Do you have a high and low side pressure gauge or just a low side. To me it shuold really be pulling the low side down to lower than even 50 and the high should around ambient air tempX2+30. So if its 80 out the high side should be somewhere around 190. I guess get your pressures off of it again and let us know...But im gonna put my money on the compressor or TXV. Put your A/C on MAX, fan on high and rev it to 2k and let me know what your pressures are. If its not making very good pressures its gotta be the compresor.

blkbird

iTrader: (28)

The low side should be at arounf 40-45psi I beleive. Did you also swp out the accumulator? I just redid mine about 4 months ago and it still blowing cold as hell. Orifice tube has to also be replaced.

I will keep this in mind if my compressor goes out again.

MattZ28

iTrader: (4)

Yes, I know this. Apparently you guys aren't reading all of my posts or something?

MattZ28

iTrader: (4)

OK I replaced the expansion valve, added 5oz PAG oil, vacuumed for 1.5hrs, about 7/8 way through the first can, the compressor kicked on for a few seconds and then shut off. After that it wouldn't take any more (tried another can) and won't kick back on. Earlier today the compressor stopped kicking on as well. Now what? Ugh...

Joey7489

iTrader: (21)

you might have l ocked the compressor up :-/.. it happened to my grandpas car and now he needs a new one