Air Conditioning Dilemma
08-30-2006, 07:34 PM
#1
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Join Date: May 2004
Posts: 10
Air Conditioning Dilemma
I have a '79 280ZX with the factory air and it has been working but was not as cool as I would like (given the 100 degree weather we have had all summer here in San Antonio). So I took the car to a known AC specialist to see if possibly it just needed some refrigerant. It was low so (about half full) so they filled it as well as putting in some dye in case there was a leak and also added oil.
After paying $92 I drove away really happy as the temperature was very cold. Later that same day I got in the car and started the AC and nothing but hot air came out. So I took it back to the guy and he verifies that there isn't a leak, that it still has all of the refrigerant. According to him it isn't cooling because it is "going in to a vacuum and there is a restriction that is stopping up the system". Essentiall he says that there is no fluid going into the evaporator so it won't cool. He thinks the problem is the POA/STV Valve (and the expansion valve or a combination of the two). At any rate he also says that it doesn't appear that you can remove the POA valve from the Evaporator and that the only possibility is a working used complete unit (unless someone out there knows of a kit to fix the POA valve).
My question is whether this makes sense to anyone out there and/or does someone have a solution to this problem. And lastly, what are my options for getting AC in the car if this unit cannot be fixed. Any help that anyone can offer will really be appreciated.
Thanks!
After paying $92 I drove away really happy as the temperature was very cold. Later that same day I got in the car and started the AC and nothing but hot air came out. So I took it back to the guy and he verifies that there isn't a leak, that it still has all of the refrigerant. According to him it isn't cooling because it is "going in to a vacuum and there is a restriction that is stopping up the system". Essentiall he says that there is no fluid going into the evaporator so it won't cool. He thinks the problem is the POA/STV Valve (and the expansion valve or a combination of the two). At any rate he also says that it doesn't appear that you can remove the POA valve from the Evaporator and that the only possibility is a working used complete unit (unless someone out there knows of a kit to fix the POA valve).
My question is whether this makes sense to anyone out there and/or does someone have a solution to this problem. And lastly, what are my options for getting AC in the car if this unit cannot be fixed. Any help that anyone can offer will really be appreciated.
Thanks!
08-30-2006, 07:43 PM
#2
I kinda had the same prob w/ my 81 280zx's a/c (before I removed it completely). I got my a/c charged w/ R12 (this was in the mid 90's before it got outrageosly expensive) and it still didn't blow cold. When I'd turn on the a/c, a nice "GRRRRRRRRRR!!!!" sound came from under the dash. After some tech'ing, found out that the valve in the evaporator was clogged. I worked for Nissan @ the time & was quoted about $90 for it. I never got around to it & eventually removed it all w/ my turbo swap.
Long story short... yep, it's possible. If that is the prob, the system will need to be evac'd to replace the part. Oh the joys of having old school a/c.
Long story short... yep, it's possible. If that is the prob, the system will need to be evac'd to replace the part. Oh the joys of having old school a/c.
08-30-2006, 07:46 PM
#3
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Join Date: Apr 2005
Location: Temecula, CA
Posts: 5,485
It makes sense and expansion valves can plug up and restrict flow. More commonly is that they freeze up though (from moisture getting in the system usually) and that is what blocks the valve. Also, if they overfilled the system then that can cause pressure problems.
As far as whether the valve is one piece with the evaporator: That I cant answer as I have never examined the unit on these cars. But most POA valves on older imports are adjustable...so it wouldn't make sense that its not servicable.
Verify that they refilled the system with R12 as it's possible what they put into the system may not be compatible with your expansion valve. Also, verify that they used the proper oil for the system. I only bring this up because it takes foreign debris to plug something like the expansion valve up. Which asks the question: How did foreign debris get into the system if they verified that the system is not leaking which means there is no entrance for a conatminant to plug the valve. Corrosion could be a cause, but not if you've been using the system.
As far as whether the valve is one piece with the evaporator: That I cant answer as I have never examined the unit on these cars. But most POA valves on older imports are adjustable...so it wouldn't make sense that its not servicable.
Verify that they refilled the system with R12 as it's possible what they put into the system may not be compatible with your expansion valve. Also, verify that they used the proper oil for the system. I only bring this up because it takes foreign debris to plug something like the expansion valve up. Which asks the question: How did foreign debris get into the system if they verified that the system is not leaking which means there is no entrance for a conatminant to plug the valve. Corrosion could be a cause, but not if you've been using the system.
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