A/C compressor bench test?
Thread Starter
Pro
Joined: Jun 2010
Posts: 535
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From: CA
A/C compressor bench test?
ok im trying to diagnose some A/c stuff before i put it all back together. im trying to figure out if the compressor works. if i apply 12 volts to the a/c compressor plug the a/c compressor makes a click noise. if i look at it when i apply 12v the clutch sucks in maybe 1/4 inch to 1/2 inch. does this mean my compressor at least works? i know when its running properly the a/c clutch sucks all the way in but i assume when bench testing if it just moves a little it is good... can any one help me out
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
The clutch is engaging when you hear the click....
Compressing?? that depends on if you turn it will it compress gas.
If you turn it fast enough it will always compress to a degree......even if it is completely worn out.....
But if it is turning slowly will it compress.....I guess if there is a large nut that holds the shaft, you could apply your 12v to engage the clutch and then use a drill with a socket on the end to turn that nut thereby spinning the compressor to see if you get any kind of suction or compression out of it.
The Black round type is (forget the names, SunCr knows them) are only $250 for a new one at this OEM GM supply house I know of in Huntington Beach.
Compressing?? that depends on if you turn it will it compress gas.
If you turn it fast enough it will always compress to a degree......even if it is completely worn out.....
But if it is turning slowly will it compress.....I guess if there is a large nut that holds the shaft, you could apply your 12v to engage the clutch and then use a drill with a socket on the end to turn that nut thereby spinning the compressor to see if you get any kind of suction or compression out of it.
The Black round type is (forget the names, SunCr knows them) are only $250 for a new one at this OEM GM supply house I know of in Huntington Beach.
Thread Starter
Pro
Joined: Jun 2010
Posts: 535
Likes: 0
From: CA
The clutch is engaging when you hear the click....
Compressing?? that depends on if you turn it will it compress gas.
If you turn it fast enough it will always compress to a degree......even if it is completely worn out.....
But if it is turning slowly will it compress.....I guess if there is a large nut that holds the shaft, you could apply your 12v to engage the clutch and then use a drill with a socket on the end to turn that nut thereby spinning the compressor to see if you get any kind of suction or compression out of it.
The Black round type is (forget the names, SunCr knows them) are only $250 for a new one at this OEM GM supply house I know of in Huntington Beach.
Compressing?? that depends on if you turn it will it compress gas.
If you turn it fast enough it will always compress to a degree......even if it is completely worn out.....
But if it is turning slowly will it compress.....I guess if there is a large nut that holds the shaft, you could apply your 12v to engage the clutch and then use a drill with a socket on the end to turn that nut thereby spinning the compressor to see if you get any kind of suction or compression out of it.
The Black round type is (forget the names, SunCr knows them) are only $250 for a new one at this OEM GM supply house I know of in Huntington Beach.
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
Here it is.....
Dealer's Source Distributors
(714) 843-0012
18112 Gothard Street
Huntington Beach, CA 92648
Dealer's Source Distributors is a business dealing in the Auto Parts & Supplies industry. Dealer's Source Distributors is located in Huntington Beach, CA on 18112 Gothard Street.
Dealer's Source Distributors telephone number is
(714) 843-0012.
They are a place for jobbers and dealers so it may be hard to get then to ship to you......
You can see the ACDelco sign from the street view in this google map
http://www.google.com/maps?q=Dealer%...13,-117.999824
Dealer's Source Distributors
(714) 843-0012
18112 Gothard Street
Huntington Beach, CA 92648
Dealer's Source Distributors is a business dealing in the Auto Parts & Supplies industry. Dealer's Source Distributors is located in Huntington Beach, CA on 18112 Gothard Street.
Dealer's Source Distributors telephone number is
(714) 843-0012.
They are a place for jobbers and dealers so it may be hard to get then to ship to you......
You can see the ACDelco sign from the street view in this google map
http://www.google.com/maps?q=Dealer%...13,-117.999824
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
They sell things to me with a wink and cash and will call.....
I've been able to take back poorly fitting NAPA products get my money back and for the same price buy a GM Genuine part that actually fits.
The last time I had to go there was when I did my Slave Cylinder.....the NAPA had a standard hose fitting.....if you look at the end of an early C4 clutch hose, it has an aluminum block on it.....won't work with the NAPA Slave......GM part was identical to what I took off.
That is when I saw the A/C units for $250 and made a mental note to buy one when my failing unit completely failed (and it has).....
I've been able to take back poorly fitting NAPA products get my money back and for the same price buy a GM Genuine part that actually fits.
The last time I had to go there was when I did my Slave Cylinder.....the NAPA had a standard hose fitting.....if you look at the end of an early C4 clutch hose, it has an aluminum block on it.....won't work with the NAPA Slave......GM part was identical to what I took off.
That is when I saw the A/C units for $250 and made a mental note to buy one when my failing unit completely failed (and it has).....
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Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
ok im trying to diagnose some A/c stuff before i put it all back together. im trying to figure out if the compressor works. if i apply 12 volts to the a/c compressor plug the a/c compressor makes a click noise. if i look at it when i apply 12v the clutch sucks in maybe 1/4 inch to 1/2 inch. does this mean my compressor at least works? i know when its running properly the a/c clutch sucks all the way in but i assume when bench testing if it just moves a little it is good... can any one help me out
If the compressor turns then it is not seized up. Place you thumb over the intake port (that would be the pipe coming from the evaporator and accumulator) and rotate the shaft in the direction it would turn with the engine. If it creates a good suction and feels smooth, then it is probably working. You can try the same test with the output port and feel a pressure.
That is a quick check and about the best you can do on the bench with limited test equipment.
Thread Starter
Pro
Joined: Jun 2010
Posts: 535
Likes: 0
From: CA
Sounds like the clutch is basically working. If it does not smell as if it burnt, it is probably OK.
If the compressor turns then it is not seized up. Place you thumb over the intake port (that would be the pipe coming from the evaporator and accumulator) and rotate the shaft in the direction it would turn with the engine. If it creates a good suction and feels smooth, then it is probably working. You can try the same test with the output port and feel a pressure.
That is a quick check and about the best you can do on the bench with limited test equipment.
If the compressor turns then it is not seized up. Place you thumb over the intake port (that would be the pipe coming from the evaporator and accumulator) and rotate the shaft in the direction it would turn with the engine. If it creates a good suction and feels smooth, then it is probably working. You can try the same test with the output port and feel a pressure.
That is a quick check and about the best you can do on the bench with limited test equipment.
next question:
when the a/c compressor was on the vehicle (system had 0 pressure) you could kind of sort of hear the compressor pulley turn, almost like rocks but not very loud and not all the time. do you think this is just a lack of oil issue and will straiten itself out once all the oil is back in there? or are the bearings shot?
Thread Starter
Pro
Joined: Jun 2010
Posts: 535
Likes: 0
From: CA
Here it is.....
Dealer's Source Distributors
(714) 843-0012
18112 Gothard Street
Huntington Beach, CA 92648
Dealer's Source Distributors is a business dealing in the Auto Parts & Supplies industry. Dealer's Source Distributors is located in Huntington Beach, CA on 18112 Gothard Street.
Dealer's Source Distributors telephone number is
(714) 843-0012.
They are a place for jobbers and dealers so it may be hard to get then to ship to you......
You can see the ACDelco sign from the street view in this google map
http://www.google.com/maps?q=Dealer%...13,-117.999824
Dealer's Source Distributors
(714) 843-0012
18112 Gothard Street
Huntington Beach, CA 92648
Dealer's Source Distributors is a business dealing in the Auto Parts & Supplies industry. Dealer's Source Distributors is located in Huntington Beach, CA on 18112 Gothard Street.
Dealer's Source Distributors telephone number is
(714) 843-0012.
They are a place for jobbers and dealers so it may be hard to get then to ship to you......
You can see the ACDelco sign from the street view in this google map
http://www.google.com/maps?q=Dealer%...13,-117.999824
thank you for all that info.... and the Google map
I called them up, not sure if im get the gringo special or just spoke to the wrong guy but i was quoted anywhere from $370-$680. I guess $370 is still better than other places and its relatively local, but for $370 im gonna have to pass and make the one i have work. if it doesn't already.
they seem like some really cool people to deal with though. thanks for the lead
i turn the compressor with a drill and it does produce vacuum, not sure how much i couldn't find a fitting that fit to put a gauge on it.
Well looks like im going to follow your advice and put some oil in it, fill it up and see what happens.
How much new oil do i put in it? I have the compressor off the car so i could drain out all the old r12 oil and flush it.
Last edited by 69SSC5; Apr 21, 2012 at 01:15 PM.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
20 plus year old mobile a/c parts are often shot - or soon will be. The knocking noise, with or without oil, says it's gone. For the price of a new one (I'm assuming this is the Harrison R4 and not the Nippo 10PA20C), I wouldn't even bother trying to fix it and beyond a clutch assembly and shaft seal, the innards aren't available anyway. While you're at it, consider replacing the Condenser, schraders, all of the o-rings and Orifice and you will need a new Accumulator/Drier. That leaves the Evaporator - which unfortunately, doesn't have the best reputation, so you might remove the Blower Motor and try to visualize the intake side. If the factory foam filter (that's glued to it) is covered with gunk, it's leaking and you'll need a new one of those too.
