94 R134a AC problem
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Laughing Gas
Joined: Jun 2004
Posts: 1,240
Likes: 3
From: Dallas, Texas
94 R134a AC problem
I serviced my AC today the clutch was cycling to much and the low pressure cut- off switch was bad. So I went ahead and did my summer AC check. It was low on R134a so I put my gauges on and it showed 30 low side and 170 high at 90* air temp. It should be 45~55 low and 250 high. So I started to add some freon and the reciever/dryer stopped getting cold. With both front and rear AC on the reading is correct and not getting cold now. If I shut off the rear AC the readings drop to 30 low and starts to cycle on and off. if I turn off the front and leave the rear on its gies back to normal "full" readings.
Could one of the cans had some of that bull**** sealer and screwed my orfice tubes up? I replaced the compressor 2 years ago and the gage reading at 250~270 tells me it's fine. It was blowing cold except for the low pressure switch problem.
I don't want to change parts out without having a good idea what is causing it. I have a hunch it's a clogged orfice so that means new AC receiver/dryer, orfice, flush and vacuum and 54 ozs of freon and maybe a condenser if I get trash from flush out of it.
Thanks
Could one of the cans had some of that bull**** sealer and screwed my orfice tubes up? I replaced the compressor 2 years ago and the gage reading at 250~270 tells me it's fine. It was blowing cold except for the low pressure switch problem.
I don't want to change parts out without having a good idea what is causing it. I have a hunch it's a clogged orfice so that means new AC receiver/dryer, orfice, flush and vacuum and 54 ozs of freon and maybe a condenser if I get trash from flush out of it.
Thanks
Postmaster
Joined: Oct 2009
Posts: 3,432
Likes: 7
When I service my systems, I only use pure R-134a. The DIYer cans sold at the auto parts stores ruin stuff because your system was never meant to have a sealer in it.
I think your compressor may be fine, but it it sounds to me like you might have a contaminant in the system. If moisture is in there, it will ice up inside the system and cause restrictions that will pull the pressure really low without cooling well.
Did you replace the accumulator/drier when you replaced the compressor? If not, I would pull the system apart, replace the drier and orifice tube, and then vacuum it back down again and refill with the correct amount of oil and pure R-134a.
I think your compressor may be fine, but it it sounds to me like you might have a contaminant in the system. If moisture is in there, it will ice up inside the system and cause restrictions that will pull the pressure really low without cooling well.
Did you replace the accumulator/drier when you replaced the compressor? If not, I would pull the system apart, replace the drier and orifice tube, and then vacuum it back down again and refill with the correct amount of oil and pure R-134a.
Thread Starter
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Laughing Gas
Joined: Jun 2004
Posts: 1,240
Likes: 3
From: Dallas, Texas
When I service my systems, I only use pure R-134a. The DIYer cans sold at the auto parts stores ruin stuff because your system was never meant to have a sealer in it.
I think your compressor may be fine, but it it sounds to me like you might have a contaminant in the system. If moisture is in there, it will ice up inside the system and cause restrictions that will pull the pressure really low without cooling well.
Did you replace the accumulator/drier when you replaced the compressor? If not, I would pull the system apart, replace the drier and orifice tube, and then vacuum it back down again and refill with the correct amount of oil and pure R-134a.
I think your compressor may be fine, but it it sounds to me like you might have a contaminant in the system. If moisture is in there, it will ice up inside the system and cause restrictions that will pull the pressure really low without cooling well.
Did you replace the accumulator/drier when you replaced the compressor? If not, I would pull the system apart, replace the drier and orifice tube, and then vacuum it back down again and refill with the correct amount of oil and pure R-134a.
When I replaced the compressor 2 years ago. I replaced the dryer, orfice tube and clutch. Added 7 ozs of PAG oil. It's been working fine till I notice the low pressure cut-off was going out today. So I replaced the switch and checked the AC system while I had the hood up. from the gauges reading it was low. so I started to add a can of freon that was only freon. Then the dryer went from cool to warm and never got cold again. there seems to be an abstruction in the system now. I pulled the freon out, checked the front orfice and replaced it. seems there is no rear orfice. I was told some Aerostars don't have them. went to do a total recharge and the damn low side is taking 20 mins to take one can now. I did jump the switch to get the compressor clutch to engage but it still not taking freon fast at all so I stopped right there. I think the dryer clogged up or the condenser. I do know the orfice is in the correct way to. AC has always been my nemesis, I hate troubleshooting with parts replacement.
Postmaster
Joined: Oct 2009
Posts: 3,432
Likes: 7
What brand compressor did you used? I used a 4seasons compressor in my '96 Taurus, and it lasted about a year and a half. The second time around I used a Motorcraft compressor and it has worked perfectly since.
So let me get this straight, your system was low (how low), which you noticed after you replaced the low side pressure switch. So you added more refrigerant, and now the compressor is running but the system is not getting cold?
You either have contaminants in the system, or you are overcharged. It is possible you have a system restriction, but maybe you need more? If the system is actually restricted, the pressure should keep building on the high side, but will be really low on the low side. If you are not getting airflow through the condenser while you are filling it, your pressure readings will be inaccurate and the system won't work correctly, so get a big box fan and try to get some airflow through the condenser and radiator. This is a huge part of why I converted mine to an electric fan, with the stock fan when the van was stopped the AC pretty much quit working entirely.
So let me get this straight, your system was low (how low), which you noticed after you replaced the low side pressure switch. So you added more refrigerant, and now the compressor is running but the system is not getting cold?
You either have contaminants in the system, or you are overcharged. It is possible you have a system restriction, but maybe you need more? If the system is actually restricted, the pressure should keep building on the high side, but will be really low on the low side. If you are not getting airflow through the condenser while you are filling it, your pressure readings will be inaccurate and the system won't work correctly, so get a big box fan and try to get some airflow through the condenser and radiator. This is a huge part of why I converted mine to an electric fan, with the stock fan when the van was stopped the AC pretty much quit working entirely.
Thread Starter
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Laughing Gas
Joined: Jun 2004
Posts: 1,240
Likes: 3
From: Dallas, Texas
Well today I start it up to check pressure and the damn accumulator is getting cold now with just 2 cans of freon in it and its blowing some cold air. It's not freezing cold but it cold. I checked the orfice tube connection and its getting cold on the accumulator inlet side and and hot on the condenser side at 77 degrees outside air temp.
What bugs me is I get the dealer saying 54 oz of freon for dual systems and the manual says 70. but none can tell me under what conditions these numbers apply.
I'm wondering if I have a restricted expansion valve and hose assembly on the high side on the compressor. it's the only thing I didn't replace and now it's showing its ugly head.
What bugs me is I get the dealer saying 54 oz of freon for dual systems and the manual says 70. but none can tell me under what conditions these numbers apply.
I'm wondering if I have a restricted expansion valve and hose assembly on the high side on the compressor. it's the only thing I didn't replace and now it's showing its ugly head.
Thread Starter
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Laughing Gas
Joined: Jun 2004
Posts: 1,240
Likes: 3
From: Dallas, Texas
What brand compressor did you used? I used a 4seasons compressor in my '96 Taurus, and it lasted about a year and a half. The second time around I used a Motorcraft compressor and it has worked perfectly since.
So let me get this straight, your system was low (how low), which you noticed after you replaced the low side pressure switch. So you added more refrigerant, and now the compressor is running but the system is not getting cold?
You either have contaminants in the system, or you are overcharged. It is possible you have a system restriction, but maybe you need more? If the system is actually restricted, the pressure should keep building on the high side, but will be really low on the low side. If you are not getting airflow through the condenser while you are filling it, your pressure readings will be inaccurate and the system won't work correctly, so get a big box fan and try to get some airflow through the condenser and radiator. This is a huge part of why I converted mine to an electric fan, with the stock fan when the van was stopped the AC pretty much quit working entirely.
So let me get this straight, your system was low (how low), which you noticed after you replaced the low side pressure switch. So you added more refrigerant, and now the compressor is running but the system is not getting cold?
You either have contaminants in the system, or you are overcharged. It is possible you have a system restriction, but maybe you need more? If the system is actually restricted, the pressure should keep building on the high side, but will be really low on the low side. If you are not getting airflow through the condenser while you are filling it, your pressure readings will be inaccurate and the system won't work correctly, so get a big box fan and try to get some airflow through the condenser and radiator. This is a huge part of why I converted mine to an electric fan, with the stock fan when the van was stopped the AC pretty much quit working entirely.
Well after some research, I think the condenser is the problem and needs to be replaced. some people think the system failed before I bought it and they never replaced it and its probably old anyways.
I will convert the fan to electric sometime soon. I found Lincoln fans are perfect for this type of conversion. and u need to do my transmission cooler to electric anyways while I'm in there and bypass that stupid threw the radiator which is hot and does nothing for cooling.
Thread Starter
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Laughing Gas
Joined: Jun 2004
Posts: 1,240
Likes: 3
From: Dallas, Texas
Well after some research, I think the condenser is the problem and needs to be replaced. some people think the system failed before I bought it and they never replaced it and its probably old anyways.
I will convert the fan to electric sometime soon. I found Lincoln fans are perfect for this type of conversion. and u need to do my transmission cooler to electric anyways while I'm in there and bypass that stupid threw the radiator which is hot and does nothing for cooling.
I will convert the fan to electric sometime soon. I found Lincoln fans are perfect for this type of conversion. and u need to do my transmission cooler to electric anyways while I'm in there and bypass that stupid threw the radiator which is hot and does nothing for cooling.
I fixed it. The damn thing had to much oil in it. some how it got flooded and was restricting the system.
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Post Fiend
Joined: Apr 2005
Posts: 5,720
Likes: 5
From: Washington state
hard to get all the old oil out especially with the dual Aero option rear A/C.
old oil left in + new oil with new comp + new oil in most of the auto parts pop can freon adds =s too much oil.
pays to completely take these Aero systems totally apart and flush each individual item including the hoses which have built in can filters which may not clean. critically with the dual Aero option system after a compressor failure
so many low spots and collection points in the dual option Aero system for oil to collect and settle out.
old oil left in + new oil with new comp + new oil in most of the auto parts pop can freon adds =s too much oil.
pays to completely take these Aero systems totally apart and flush each individual item including the hoses which have built in can filters which may not clean. critically with the dual Aero option system after a compressor failure
so many low spots and collection points in the dual option Aero system for oil to collect and settle out.
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