Another AC Question
Thread Starter
Racer
Joined: Feb 2014
Posts: 285
Likes: 0
From: Las Vegas, NV
Another AC Question
I am thinking about taking my 1984 928S in for AC service. I pushed the valve in on the low pressure port and there was still pressure in there with gas and oil coming out of the port. Can I assume that the system is not leaking? The AC hasn't been used in 17 years.
Nordschleife Master
Joined: May 2012
Posts: 5,222
Likes: 432
From: Thousand Oaks California
you could, but I would replace the o-rings and compressor oil for peace of mind.
I was in the same situation you are in and I replaced almost my entire a/c system so I could have peace of mind and have a functional r134 system.
If you fill up with r12, just service system, the oil can break down over 17+ years and the o-rings could be 30 years old.
I was in the same situation you are in and I replaced almost my entire a/c system so I could have peace of mind and have a functional r134 system.
If you fill up with r12, just service system, the oil can break down over 17+ years and the o-rings could be 30 years old.
Rennlist Member
Joined: Jun 2004
Posts: 1,080
Likes: 62
Hayden,
Assuming you don't have any repair order records on what has been done in the past, and the system is original:
New barrier hoses for compressor to condenser and compressor to evaporator pipe. New o-rings. New drier. Maybe a seal kit for the compressor depending upon its condition; if it has high miles budget for new. Possibly liquid flush the system if there are signs of contamination.
If the system has already been converted to R134a you will want to know what type of refrigerant oil was used (PAG or Ester; the preference is not mix the two).
Any AC shop can evacuate, charge and test, sniff for leaks and observe performance.
Knowledge of the AC climate controls, such as servo's, vacuum modules, etc in the center console (found here and on Pelican) will come in very handy.
Average worse case scenario on a typical Shark of this age is:
Compressor, Drier, Hoses, O-rings.
The condenser maybe starting to have brazed joint issues.
Front evaporator's seldom fail.
PM if you need more help
Assuming you don't have any repair order records on what has been done in the past, and the system is original:
New barrier hoses for compressor to condenser and compressor to evaporator pipe. New o-rings. New drier. Maybe a seal kit for the compressor depending upon its condition; if it has high miles budget for new. Possibly liquid flush the system if there are signs of contamination.
If the system has already been converted to R134a you will want to know what type of refrigerant oil was used (PAG or Ester; the preference is not mix the two).
Any AC shop can evacuate, charge and test, sniff for leaks and observe performance.
Knowledge of the AC climate controls, such as servo's, vacuum modules, etc in the center console (found here and on Pelican) will come in very handy.
Average worse case scenario on a typical Shark of this age is:
Compressor, Drier, Hoses, O-rings.
The condenser maybe starting to have brazed joint issues.
Front evaporator's seldom fail.
PM if you need more help
Rennlist Member
Joined: May 2012
Posts: 319
Likes: 2
From: 88 928 S4 in Dallas, TX
If the system is holding pressure, is it functioning? Need more information.
In my case, the system was just low and freon so all I needed to do is top it up. Then it appeared to function poorly until I zip tied the heater valve shut as it would never seem to fully close.
Now it's so cold, that I have to hold the steering wheel at the bottom to avoid the cold air from the vents.
I get nervous when I hear terms like "A/C service". To me, this means a big vinyl poster outside an oil change place offering a vacuum for $29.99 and recharge with R134a for an extra x number of $ per pound. With the guy performing the work usually having no idea of what he's doing.
If the system is holding a charge, I would think a much safer bet would be to source some R12 and top it up. Then enjoy the system in the way that the factory designed it.
In any case, we need more info to about why you have not used the system in 17 years.....Especially in Vegas.
In my case, the system was just low and freon so all I needed to do is top it up. Then it appeared to function poorly until I zip tied the heater valve shut as it would never seem to fully close.
Now it's so cold, that I have to hold the steering wheel at the bottom to avoid the cold air from the vents.
I get nervous when I hear terms like "A/C service". To me, this means a big vinyl poster outside an oil change place offering a vacuum for $29.99 and recharge with R134a for an extra x number of $ per pound. With the guy performing the work usually having no idea of what he's doing.
If the system is holding a charge, I would think a much safer bet would be to source some R12 and top it up. Then enjoy the system in the way that the factory designed it.
In any case, we need more info to about why you have not used the system in 17 years.....Especially in Vegas.
Thread Starter
Racer
Joined: Feb 2014
Posts: 285
Likes: 0
From: Las Vegas, NV
That would be great if you could show me how to use them or help me with this. I am willing to pay for your help....Are you able to vacuum test the system with what you have?
Instructor
Joined: May 2010
Posts: 150
Likes: 1
From: Up North
I have the vacuum pump also. But if you are going to go to the effort and expense of evacuating your system and refilling it, you might as well change o-rings and seals. If it needs to be evacuated and re-charged, it needs new seals. No charge, glad to help.
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Racer
Joined: Feb 2014
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From: Las Vegas, NV
I was assuming the vacuum would be used to check the system for leaks. As of right now the clutch does not engage at all. I assume I can jump the low pressure switch to see if it engages?
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Track Day
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Yes you should be able to jumper the switch to simulate it closed. But also use a volt meter to verify you have voltage engaging the pump.
The vacuum is an okay way for major leaks. But seals can be bad when there is pressure at operating speeds and hold just fine under vacuum. Vacuum tends to pull everything together. The main reason for vacuum is to remove all air and moisture.
If you want to check for leaks pressurize the system with nitrogen and use a soapy solution on all the joints and seal areas. Also check the valves in the line. Only use 90 - 100 psi though.
The vacuum is an okay way for major leaks. But seals can be bad when there is pressure at operating speeds and hold just fine under vacuum. Vacuum tends to pull everything together. The main reason for vacuum is to remove all air and moisture.
If you want to check for leaks pressurize the system with nitrogen and use a soapy solution on all the joints and seal areas. Also check the valves in the line. Only use 90 - 100 psi though.
Thread Starter
Racer
Joined: Feb 2014
Posts: 285
Likes: 0
From: Las Vegas, NV
I guess it is good news....I jumped the low pressure switch and the clutch engages. What are your thoughts on attempting to get the system vacuumed and charged at this point? I am thinking that the system is holding pressure based on there still being some refrigerant still in the system....
Thread Starter
Racer
Joined: Feb 2014
Posts: 285
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From: Las Vegas, NV
Glenn...Thank you for the very generous offer....perhaps I can help you in return for any assistance you can provide....maybe an extra set of hands with any work you are doing. I am a residential electrician and would be willing to help you out with electrical work as well.
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From: Incline Village N. V 89451
Hi I do not know much about this can you tell me where the high side line is an does each line end have a o-ring on them an where are the seals are they on the compressor. Thanks Vernon.