A/C issues: new compressor, still no cold air
07-27-11 | 06:47 PM
#26
No, I'm not using a machine, but I am using a pump to pull a vacuum on the system greater than 25 inHG. The system has held this vacuum for days on end, hence why I never once asked "Do I have a leak?..."
We let the vacuum pull in as much fluid as it can (and obviously, the gas in the can expands into the system until pressure in the system reaches the static pressure in the can - about 110psi in this weather). Then the car gets turned on to allow the compressor to draw in more fluid. It's not like I'm just sticking a can on the car without evacuating my system first...
Doing it this way has worked for the person who's helping me for as long as he's had his car (single-owner R1). He's recharged twice from what I remember, same old drier. Works better than the AC in my DD (1997 Mercedes C280).
I reread my own thread, you are right, it was never mentioned. My bad on that. Thanks for helping and pointing it out. My apologies for being hostile.
In the meantime, I have purchased the proper AC cleaning fluid as well as new PAG 100 oil. Will be cleaning the condensor and replacing the drier this Friday. Then PULLING A >25inHG VACUUM, leak testing, etc.
P.S. I have had 3 separate bad experiences bringing this car to a "professional" shop here in Katy and Houston. Unless the shop wants to let me use their equipment, this car is never going to another shop again. Too many incompetent or lazy "certified" technicians here.
We let the vacuum pull in as much fluid as it can (and obviously, the gas in the can expands into the system until pressure in the system reaches the static pressure in the can - about 110psi in this weather). Then the car gets turned on to allow the compressor to draw in more fluid. It's not like I'm just sticking a can on the car without evacuating my system first...
Doing it this way has worked for the person who's helping me for as long as he's had his car (single-owner R1). He's recharged twice from what I remember, same old drier. Works better than the AC in my DD (1997 Mercedes C280).
I reread my own thread, you are right, it was never mentioned. My bad on that. Thanks for helping and pointing it out. My apologies for being hostile.
In the meantime, I have purchased the proper AC cleaning fluid as well as new PAG 100 oil. Will be cleaning the condensor and replacing the drier this Friday. Then PULLING A >25inHG VACUUM, leak testing, etc.
P.S. I have had 3 separate bad experiences bringing this car to a "professional" shop here in Katy and Houston. Unless the shop wants to let me use their equipment, this car is never going to another shop again. Too many incompetent or lazy "certified" technicians here.
I would suggest though trying to see if some local places will let you use their machine or at least allow you to assist. I was lucky enough to have a Goodyear here in town that allowed me to do so. I used to be ASE certified in A/C work.
One of the problems of using the cans at home system is that you can never pull enough vacuum or keep the vacuum while pushing in the refrigerant. Running the compressor with less than adequate amounts of oil and refrigerant can stress it and cause problems.
I know the expansion valve has been a culprit to many people when their A/C goes bad or has problems recharging. Unfortunately for us, the valve is located in the evaporator (if I recall) and it is a straight bitch to get to and replace.
Also one thing that is usually over looked is a possible bad schrader valve...
Good luck.
07-27-11 | 09:26 PM
#27
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Know anywhere that has the proper one? I know it's NLA from Mazda, but what about anywhere else?
07-27-11 | 09:33 PM
#28
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No problem.
I would suggest though trying to see if some local places will let you use their machine or at least allow you to assist. I was lucky enough to have a Goodyear here in town that allowed me to do so. I used to be ASE certified in A/C work.
One of the problems of using the cans at home system is that you can never pull enough vacuum or keep the vacuum while pushing in the refrigerant. Running the compressor with less than adequate amounts of oil and refrigerant can stress it and cause problems.
I know the expansion valve has been a culprit to many people when their A/C goes bad or has problems recharging. Unfortunately for us, the valve is located in the evaporator (if I recall) and it is a straight bitch to get to and replace.
Also one thing that is usually over looked is a possible bad schrader valve...
Good luck.
I would suggest though trying to see if some local places will let you use their machine or at least allow you to assist. I was lucky enough to have a Goodyear here in town that allowed me to do so. I used to be ASE certified in A/C work.
One of the problems of using the cans at home system is that you can never pull enough vacuum or keep the vacuum while pushing in the refrigerant. Running the compressor with less than adequate amounts of oil and refrigerant can stress it and cause problems.
I know the expansion valve has been a culprit to many people when their A/C goes bad or has problems recharging. Unfortunately for us, the valve is located in the evaporator (if I recall) and it is a straight bitch to get to and replace.
Also one thing that is usually over looked is a possible bad schrader valve...
Good luck.
You are right, the expansion valve is in the evaporator assembly, but I don't think it's that bad to get to. The worst part is disconnecting the two AC lines in the engine bay, since my ABS and secondary intake pipe get in the way.
The Schrader valves are new as well. The low side was bad when we started this whole debacle...
The compressor has plenty of oil, but you are right, it would be better to run it with more fluid. I think it will be fine, though, since my friend's has lasted quite some time.
Thanks for the good luck, I need it at this point...
07-28-11 | 06:33 AM
#29
Last year, I ordered an (ill fitting) MANA dryer from CSK Auto's site. When I ordered, their site was on its last legs as far as inventory is concerned, and the CSK site now appears to be fully absorbed into the O'Reilly site. Ray at Malloy had some made, but when I talked to him the other day, he had sold through them all a while back, and the company that made them had gotten out of that business.
Did you ever dig up that thread you mentioned about making the other dryer work? I'm curious to read what exactly is going on with that.
07-28-11 | 11:11 AM
#30
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Yeah...I'm not sure why the parts books list a different drier for the Denso systems for '93 vs '94/'95. I would guess it had something to do with the refrigerant switchover. I've yet to compare them side by side.
Did you ever dig up that thread you mentioned about making the other dryer work? I'm curious to read what exactly is going on with that.
Did you ever dig up that thread you mentioned about making the other dryer work? I'm curious to read what exactly is going on with that.
https://www.rx7club.com/showthread.p...ighlight=dryer
Look at who entered the last post.
Sadly, that must have been the ill fitting dryer you are referring to. NLA from O'Reilly.I have heard many conflicting sources about what defines a MANA AC system and a NipponDenso AC system, aside from prices. From all that I have read, it seems like I have mostly MANA parts, with some NipponDenso parts thrown into the mix. Based on this, I'm going to try the dryer at O'Reilly anyways. If it doesn't fit, I can just return it.
07-28-11 | 12:24 PM
#31
I have heard many conflicting sources about what defines a MANA AC system and a NipponDenso AC system, aside from prices. From all that I have read, it seems like I have mostly MANA parts, with some NipponDenso parts thrown into the mix. Based on this, I'm going to try the dryer at O'Reilly anyways. If it doesn't fit, I can just return it.
The MANA system has a drier which is usually black in color, and the bracket that holds the drier to the car is welded to the drier itself. On R-12 cars, the sight glass is on a little cube in the line to the side of the drier. The MANA system also has a bulb type TXV with an external equalizer tube.
The Nippondenso system has a drier which is silver and slips into a holder which then bolts to the car. The sight glass is in the top of the block that bolts directly to the drier. The TXV for the Nippondenso system is the oh-so-clever block type....a rectangle of aluminum with 4 holes in it that sandwiches between the lineset and the evaporator core.
All the other parts except for the compressor are different, too....but the differences there are much harder to identify.
07-30-11 | 07:06 PM
#32
However, this still did not help my AC issues. There are two more things I have not replaced - the condensor and the dryer. The high side condensor line is slightly crimped, but my friend cewrx7r1 said he has a worse crimp in his and his AC still works. We're thinking maybe the condensor or dryer are gunked up pretty bad, but still flow well enough to allow some flow. Going to try to source a condensor. Can get a dryer locally. Or maybe have someone make a custom condensor.
Ryan1 - not ruling out the compressor, just trying to eliminate less costly items first. The condensor and dryer also happen to be the two components I have not replaced.
If the crimp line is bad enough to cause you a problem, it will have a frost ring there as it is a restriction. It would also cause high, high side pressure. If the dryer is a restriction you should see very low low side, dipping into vac. before the compressor kicks out.
Ryan1 - not ruling out the compressor, just trying to eliminate less costly items first. The condensor and dryer also happen to be the two components I have not replaced.
If the crimp line is bad enough to cause you a problem, it will have a frost ring there as it is a restriction. It would also cause high, high side pressure. If the dryer is a restriction you should see very low low side, dipping into vac. before the compressor kicks out.
07-31-11 | 11:23 AM
#33
Enthalpy ended up coming over to my place yesterday afternoon, and we had a 12 hour A/C system swap marathon.
As it turns out, his reman'd compressor was indeed bad....it had excessive amounts of what I would call "blow-by" I could put my thumb on the discharge port and rotate the hub by hand and you could hear the pressure escaping back out the suction port.
As it turns out, his reman'd compressor was indeed bad....it had excessive amounts of what I would call "blow-by" I could put my thumb on the discharge port and rotate the hub by hand and you could hear the pressure escaping back out the suction port.
08-01-11 | 11:19 AM
#35
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For the most part. The pressure switch seems to be cycling, but this is a minor issue. Probably a case of loading a little too much refrigerant.
You were right about the compressor, but the MANA drier was old, and very hard to find a replacement for.
So yes, I went to JM1FD's place to swap my old system out. But I should also mention that we switched from MANA to NipponDenso systems - so now I have a much more easily replacable drier. It required a bit of modification to fit with the airbag, but aside from that, it is a plug and play conversion. Lines also needed a lot of bending to fit my front mount, but all of the bends are very gradual - there are no crimps like there were on my old setup.
Still need to sheath some lines and make brackets for others to protect them. Then add some ducting to the condensor and radiator to allow the radiator fans to pull more air through the condensor... But aside from all that, it works REALLY well.
You were right about the compressor, but the MANA drier was old, and very hard to find a replacement for.
So yes, I went to JM1FD's place to swap my old system out. But I should also mention that we switched from MANA to NipponDenso systems - so now I have a much more easily replacable drier. It required a bit of modification to fit with the airbag, but aside from that, it is a plug and play conversion. Lines also needed a lot of bending to fit my front mount, but all of the bends are very gradual - there are no crimps like there were on my old setup.
Still need to sheath some lines and make brackets for others to protect them. Then add some ducting to the condensor and radiator to allow the radiator fans to pull more air through the condensor... But aside from all that, it works REALLY well.
08-01-11 | 03:39 PM
#37
Not just because of the dryer. His condenser was potentially contaminated because the first compressor had a mechanical failure. The rest of the system had suffered through numerous line ruptures and repairs, and needed to be removed and completely flushed to get back to a known state.
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