A/C Problems
06-30-2001, 08:40 PM
#1
Track Day
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A/C Problems
It hit 95+ here on the east coast today. My 82's a/c just couldn't keep up. This was the first real test of the season. The air blowing from the vents was barely cool (usually its ice cold!). I immediately checked the fuses; they looked good but replaced them anyway (made no difference). The electric fan also was not running, I believe it should when ever the a/c is on. And the compressor did not cycle. In checking the site glass, the coolant looked "foamy" (indicating a partial discharge). Here are my ?s:
1. Am I correct that these symptoms are typical of a discharged system?
2. If so, can I trust my 82 to the corner service station to pressure/temp check the system and recharge it or should I take it to the nearest Porsche dealer for the check and repair? (I've been burned on lack of experience = high labor charges by non-Porsche shops in the past, so I'm a bit cautious here.)
3. Is there anything else I should consider, like replacing the evaporator as a routine pre-caution? Have also consider R134, but would rather pay the price for R12.
Thanks!!
Rich
1. Am I correct that these symptoms are typical of a discharged system?
2. If so, can I trust my 82 to the corner service station to pressure/temp check the system and recharge it or should I take it to the nearest Porsche dealer for the check and repair? (I've been burned on lack of experience = high labor charges by non-Porsche shops in the past, so I'm a bit cautious here.)
3. Is there anything else I should consider, like replacing the evaporator as a routine pre-caution? Have also consider R134, but would rather pay the price for R12.
Thanks!!
Rich
06-30-2001, 09:57 PM
#2
Three Wheelin'
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I definately wouldn't trust the car to the corner gas station shop, and I'd even be weary of the dealership mechanics. When's the last time any of them saw anything except a Boxster or 993 on their lift?
Find out who the reputable 928 mechanics are in your area and go with them. Also, I just had my 88 S4 converted to R134 and I'm out in So Cal. So far so good.
Find out who the reputable 928 mechanics are in your area and go with them. Also, I just had my 88 S4 converted to R134 and I'm out in So Cal. So far so good.
06-30-2001, 10:37 PM
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A foamy sight glass is a good indication of a low coolant charge, On the 82 the fan is temperature controlled and will only come on if the coolant reaches a certain temperature. The sensor can be checked by unscrewing it from the receiver dryer and heating it. You will feel the switch close when the heat trips it . BTW be careful when screwing it back in the receiver dryer , it doesn't take much torque to snap off a 90 dollar part BTDT. I would find a shop that is an A/C specialist , 928 A/C systems are pretty simple.
06-30-2001, 10:52 PM
#4
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Since you saw foam in the sight glass, that means that the compressor was running, which means that the freon is low, but not so low that the pressure switch killed the compressor.
A leak test and recharge seems to be in order. Unless you have a good 928 shop handy, i would go for a good A/C shop, rather than a corner garage. Nothing special about the 928's refrigeration system - except that the low side connection is hidden under the upper radiator hose on the passenger side (pretty much under the coil).
On your car, the fan is operated by freon temperature (among other things), and if the freon is low, it probably will never get hot enough to trigger the fan.
A leak test and recharge seems to be in order. Unless you have a good 928 shop handy, i would go for a good A/C shop, rather than a corner garage. Nothing special about the 928's refrigeration system - except that the low side connection is hidden under the upper radiator hose on the passenger side (pretty much under the coil).
On your car, the fan is operated by freon temperature (among other things), and if the freon is low, it probably will never get hot enough to trigger the fan.
07-09-2001, 11:18 PM
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Burning Brakes
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Originally posted by Rich:
<STRONG>It hit 95+ here on the east coast today. My 82's a/c just couldn't keep up. This was the first real test of the season. The air blowing from the vents was barely cool (usually its ice cold!). I immediately checked the fuses; they looked good but replaced them anyway (made no difference). The electric fan also was not running, I believe it should when ever the a/c is on. And the compressor did not cycle. In checking the site glass, the coolant looked "foamy" (indicating a partial discharge). Here are my ?s:
1. Am I correct that these symptoms are typical of a discharged system?
2. If so, can I trust my 82 to the corner service station to pressure/temp check the system and recharge it or should I take it to the nearest Porsche dealer for the check and repair? (I've been burned on lack of experience = high labor charges by non-Porsche shops in the past, so I'm a bit cautious here.)
3. Is there anything else I should consider, like replacing the evaporator as a routine pre-caution? Have also consider R134, but would rather pay the price for R12.
Thanks!!
Rich
</STRONG>
<STRONG>It hit 95+ here on the east coast today. My 82's a/c just couldn't keep up. This was the first real test of the season. The air blowing from the vents was barely cool (usually its ice cold!). I immediately checked the fuses; they looked good but replaced them anyway (made no difference). The electric fan also was not running, I believe it should when ever the a/c is on. And the compressor did not cycle. In checking the site glass, the coolant looked "foamy" (indicating a partial discharge). Here are my ?s:
1. Am I correct that these symptoms are typical of a discharged system?
2. If so, can I trust my 82 to the corner service station to pressure/temp check the system and recharge it or should I take it to the nearest Porsche dealer for the check and repair? (I've been burned on lack of experience = high labor charges by non-Porsche shops in the past, so I'm a bit cautious here.)
3. Is there anything else I should consider, like replacing the evaporator as a routine pre-caution? Have also consider R134, but would rather pay the price for R12.
Thanks!!
Rich
</STRONG>
07-09-2001, 11:37 PM
#6
Burning Brakes
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Sorry Folks to be clumsy in this reply. I have been away for a long time. This new interface takes some getting used to.
I have spent way too much money to count on A/C problems. I paid several mechanics to allegedly train on my A/C problems.
The FIRST PLACE TO LOOK IS VACUUM. Buy a vacuum pump (~$30 at Advance or Auto Zone). Look under the hood below the huge brake vacuum booster device - driver's side by the firewall. Remove one of the vacuum hoses from the 4 pronged connector below said device. "Pump up the Volume!" e.g. connect the pump to the open fitting and pump it up. If it leaks down right away, there are about 5 vacuum pods on your car. Any one of them will cause your A/C to fail. Do not spend any more money until you fix your vacuum problems. If this is the problem, email me, and I will help you. Solutions are not for the faint of heart. Some require removal of center console and/or instrument pod.
I have spent way too much money to count on A/C problems. I paid several mechanics to allegedly train on my A/C problems.
The FIRST PLACE TO LOOK IS VACUUM. Buy a vacuum pump (~$30 at Advance or Auto Zone). Look under the hood below the huge brake vacuum booster device - driver's side by the firewall. Remove one of the vacuum hoses from the 4 pronged connector below said device. "Pump up the Volume!" e.g. connect the pump to the open fitting and pump it up. If it leaks down right away, there are about 5 vacuum pods on your car. Any one of them will cause your A/C to fail. Do not spend any more money until you fix your vacuum problems. If this is the problem, email me, and I will help you. Solutions are not for the faint of heart. Some require removal of center console and/or instrument pod.
07-12-2001, 02:34 PM
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Cruisin'
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Hey guys! I wanted to share my two bits. I live in steamy New orleans, always in 90's with very high humidity for the summer months. I had a/c woes as well. I found a great solution in an aftermarket compressor and assembly kit form Griffith's. It is a rotary style compressor. Alos, I changed the expansion valve and all o-rings. The system works like a charm in a blk/blk 928, in ridiculous heat. I believe vertex also offers a rotary style compressor for less, but it may not have the nice laser cut mounting brackets provided with the Griffith kit. Anyway, Good luck! 
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07-12-2001, 05:05 PM
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The A/C in my '88 S4 had the same symptoms about a month ago. I was hoping it only needed a freon re-charge, but leak-down test showed the expansion valve was bad. The freon evac and re-charge plus the new valve set me back about $300 at the local independent (and trustworthy) shop. Now my shark is chillin'.
07-14-2001, 03:00 PM
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Burning Brakes
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To identify vacuum problems: On my 1986 model, there is a 4 pointed vacuum hose connector at the driver's side firewall. Pull off a hose that goes forward. Attach, and pump up your vacuum pump. If the vacuum gauge shows leakage (pressure rapidly decreases), check the control unit behind your ashtray. You may be able to access this by removing the driver's side carpeted panel below the center console. You may get a better look by removing the ash tray, and radio. However, I loosened up the center console enough to expose the control unit. On the left side is a vacuum hose that supplies the vacuum. Remove it, attach pump to control unit. Check for leakage. If it leaks down, reattach hose, and pull each hose, attach pump to hose this time, and check. The one or more that leak will identify source(s) of leaks. For me there were 2 leaking vacuum pods. I pulled the instrument pod to replace these. Note: Any leak found above causes the heater valve to blend hot and cold air improperly. It is located in the engine compartment, by the passenger firewall, beneath the air filter. You may want to leak test this component before you go to the center console area.
07-14-2001, 03:37 PM
#10
Burning Brakes
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See: http://www.nichols.nu/tips.htm
Greg Nichols home page has thorough "vacuum testing" procedures. It contains a center console removal procedure that I wrote. The instrument pod is covered under dash removal. It contains numerous other references to climate contol.
Greg Nichols home page has thorough "vacuum testing" procedures. It contains a center console removal procedure that I wrote. The instrument pod is covered under dash removal. It contains numerous other references to climate contol.
07-20-2001, 06:30 PM
#11
Track Day
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Well I got the A/C system checked by an air conditioning shop today. Ran a leak test and recharged it (it was low...not bad for 10 years!). So far so good! Its really chillin' now!! Let hope everything holds; if not, it'll go back to dig a bit deeper. Thanks to everyone that replied!!
Rich
Rich