A/C - Where is the Low pressure valve located
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I have the same question...
I have seen it stated that it is undernearth by the compresssor and some have said that its the one behind the drivers side headlight.
I have an empty system that I am doing the cheap conversion on.
Don
I have seen it stated that it is undernearth by the compresssor and some have said that its the one behind the drivers side headlight.
I have an empty system that I am doing the cheap conversion on.
Don
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On the early cars the system routing goes from compressor to condenser, to evaporator, back to receiver / drier, to compressor again. The fitting Don is mentioning is on the metal pipe right by the receiver drier and given this routing, should be suitable for charging (on top of being fairly easy to get at).
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Early cars, the port by the dryer is the high pressure port, the low pressure port is on top of the compressor where the line comes out. Just found this out yesterday from a mech at work when we recharged the system. Sure is nice to have cool air again. Took a road trip to Miami Beach today and it sure was HOT out there.
Bill
Bill
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Did you re-charge at the high compression port (easiest to get at) or the low port (on top of the compressor, hardest to get at)?
I have a Wal-Mart self re-charge can of freon I want to use to charge the system. My ac works, but not that cold.
Thanks.
I have a Wal-Mart self re-charge can of freon I want to use to charge the system. My ac works, but not that cold.
Thanks.
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I just recharged my system (low side near the driver headlight)with 134A. I was very skepticle that it would work, but it did and very well. It still leaks about 1 can (12 oz) a month. At a cost of $3.99/can it will cost about $20 to keep it charged throughout the summer. Sure beats the alternative of an expensive conversion.
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mines a early 85 944
When I hook it up to that port by the headlight, the gauge goes into the red..
It does take some gas and liquid , but only to a certain extent (allowing the compressor to come on).
The air blowing is cooler, but in no way is " Cold ".
So, it appears that you can top off a system at that port, but not a fresh fill.
How does one get to that port behind the compressor with a short hose < 1 foot ????
Can I just remove the air filter assembly ???
I have nowhere to do extensive things like jack it up or put it on ramps, I live in an apartment complex that FORBIDS it.
I did notice that the PET stated that the low pressure vavle was right next to the port by the headlight, so I assumed that that was the low pressure (suck) port..
When I hook it up to that port by the headlight, the gauge goes into the red..
It does take some gas and liquid , but only to a certain extent (allowing the compressor to come on).
The air blowing is cooler, but in no way is " Cold ".
So, it appears that you can top off a system at that port, but not a fresh fill.
How does one get to that port behind the compressor with a short hose < 1 foot ????
Can I just remove the air filter assembly ???
I have nowhere to do extensive things like jack it up or put it on ramps, I live in an apartment complex that FORBIDS it.
I did notice that the PET stated that the low pressure vavle was right next to the port by the headlight, so I assumed that that was the low pressure (suck) port..
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I tried accessing the port on the compressor, but it is in such a tight space, I couldn't get the nozzle of the refill bottle on or near it....?
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The low port on the early models is indeed on the compressor, and it is a very tight fit. The early high side port is next to the drier just behid the left headlight. On later models both service ports are by the left strut tower.
DO NOT charge through the high side port. You could end up with refrigerant going into the can instead of the car. Or worse, if you force lquid refrigerant into the compressor, it will lock up. Or worse yet, there is a real possibility that the can could explode from the high side pressure.
Someone here suggested using a shorter belt form NAPA. This is a link to the part: http://www.napaonline.com/cgi-bin/nc...grpid=79867966
I can confim that the works well. It is still a tight fit, but at least it clears the mounting ear of the alternator. Since I converted to R134a, I had to use a 90 degree fitting so that the large R134a connector. They are also available at NAPA for about $15.
Don, I don't know about your 85/1 model. If you have any type of gauge, the pressure on the low side is like 30-45 psi. On the high side, its like 150 - 250 psi. If you just have one port behid the headlight, it's probably the high side. If you remove the belt, you can swing the compressor down, install the 90 degree fitting and the new belt, tension it up, and charge from under the car. I can't imagine doing this without jacking the car.
CT944, make sure you don't mix R134a with R12. If your car has R12 in it, you can't just put a can of R134a in.
POP, the routing you describe on your 85/1 is different than my 83. There may have been a change. On my car the compressed gas goes to the condensor, liquid to the drier, expansion valve, becomes a gas again in the evaporator, and back to the compressor. You can't compress a liquid.
DO NOT charge through the high side port. You could end up with refrigerant going into the can instead of the car. Or worse, if you force lquid refrigerant into the compressor, it will lock up. Or worse yet, there is a real possibility that the can could explode from the high side pressure.
Someone here suggested using a shorter belt form NAPA. This is a link to the part: http://www.napaonline.com/cgi-bin/nc...grpid=79867966
I can confim that the works well. It is still a tight fit, but at least it clears the mounting ear of the alternator. Since I converted to R134a, I had to use a 90 degree fitting so that the large R134a connector. They are also available at NAPA for about $15.
Don, I don't know about your 85/1 model. If you have any type of gauge, the pressure on the low side is like 30-45 psi. On the high side, its like 150 - 250 psi. If you just have one port behid the headlight, it's probably the high side. If you remove the belt, you can swing the compressor down, install the 90 degree fitting and the new belt, tension it up, and charge from under the car. I can't imagine doing this without jacking the car.
CT944, make sure you don't mix R134a with R12. If your car has R12 in it, you can't just put a can of R134a in.
POP, the routing you describe on your 85/1 is different than my 83. There may have been a change. On my car the compressed gas goes to the condensor, liquid to the drier, expansion valve, becomes a gas again in the evaporator, and back to the compressor. You can't compress a liquid.
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83na944.. Thanks for your correct explanation !!!
I did indeed find the port on the compressor, and its a bastard fit..
I called AutoZone and picked up a 90 degree adapter for like $3, and it feels like I can just screw it on, but the problem is that the quick disconnect for the R134 doesn't fit the 90 degree adapter DOH !!!...
So, there is a NAPA close to me, maybe I can get one there or in my travels..
Oh, the high side was empty when I started, should I assume that there is no residual R12 on the low side? should I vent it ?? ( and watch the EPA jump out of the trees and come and get me )
I did indeed find the port on the compressor, and its a bastard fit..
I called AutoZone and picked up a 90 degree adapter for like $3, and it feels like I can just screw it on, but the problem is that the quick disconnect for the R134 doesn't fit the 90 degree adapter DOH !!!...
So, there is a NAPA close to me, maybe I can get one there or in my travels..
Oh, the high side was empty when I started, should I assume that there is no residual R12 on the low side? should I vent it ?? ( and watch the EPA jump out of the trees and come and get me )
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I have an 85.5 and the low side is just in front of the bubble sight glass in the from drivers side by the headllight. A tight fit indeed, but it does work just fine. I can't see spending the money on a conversion for three months of A/C a year. I live in a frozen tundra. The sits from late November to early spring provided the salt is gone.
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Don,
You probably got a high side R134a fitting. Its larger than the low side fitting.
I wouldn't vent it, EPA may come and get you. You really should have someone recover the R12 if you think there is any still in the system. If you're sure its empty, you should rent a vacuum pump and pull a high vacuum (like 29 in Hg) for about an hour to evaporate any water in the system. It may freeze in the evaporator or expansion valve and block the flow. If you have a fairly large compressor available, you can buy a venturi device at Harbor Freight for about $10 that will go to 28 in Hg. Not as good as a $200 pump, but it would be better than nothing.
Charge through the low side with the engine running and the ac set to the cold. The low side pressure shouldn't get over 30 - 45 psi, so there would not be much danger of exploding the can. As the refrigerant goes into the system, the can will get cold. If you set it in warm water, it will charge faster. I ended up using 3 cans, but my system was evacuated and I weighed the charge with a kitchen scale. You should try 2 cans and see if it gets cold enough for you, but I suspect you'll need another half can. BTW, I've read that R134a will not cool as well if you overcharge the system.
Good luck. Let me know if I can help.
You probably got a high side R134a fitting. Its larger than the low side fitting.
I wouldn't vent it, EPA may come and get you. You really should have someone recover the R12 if you think there is any still in the system. If you're sure its empty, you should rent a vacuum pump and pull a high vacuum (like 29 in Hg) for about an hour to evaporate any water in the system. It may freeze in the evaporator or expansion valve and block the flow. If you have a fairly large compressor available, you can buy a venturi device at Harbor Freight for about $10 that will go to 28 in Hg. Not as good as a $200 pump, but it would be better than nothing.
Charge through the low side with the engine running and the ac set to the cold. The low side pressure shouldn't get over 30 - 45 psi, so there would not be much danger of exploding the can. As the refrigerant goes into the system, the can will get cold. If you set it in warm water, it will charge faster. I ended up using 3 cans, but my system was evacuated and I weighed the charge with a kitchen scale. You should try 2 cans and see if it gets cold enough for you, but I suspect you'll need another half can. BTW, I've read that R134a will not cool as well if you overcharge the system.
Good luck. Let me know if I can help.
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83na944, you are correct, I had the position of the receiver / drier in the wrong place in my sequence - it's compressor to condenser, condenser to receiver / drier, receiver / drier to evaporator (and expansion valve), evaporator back to compressor. I have a r134a-related question about oil in the other thread it sounds like you might be able to answer (and some of which was answered here) if you don't mind taking a peek. Thanks.