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911 AC Refrigerant Recharge and Maintenance
 
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Pelican Technical Article:

911 AC Refrigerant Recharge and Maintenance

Marco Moran

Applicable Models:

Porsche 911 (1965-89)
Porsche 912 (1965-69)
Porsche 930 Turbo (1976-89)
How to successfully recharge the A/C of the Porsche 911 that use rotary compressors such as SANDEN or similar and R134A gas.

The procedure is based on using the following equipment from Interdynamics, Brooklyn NY 11232.
1)    Interdaynamics R-134a Service kit that comes with dispenser device and lowside pressure gauge.
2)    A 12 oz can of R-134A/oil charge can (contains 2oz of oil)
3)    A 12 oz can of R-134a charge can
4)    A/C test thermometer

Primis charge cans can also be used (http://www.iqproducts.com)

A/C pressure reading check

1)    Locate service low pressure service port on the compressor. The low pressure service port is usually identified by a blue cap. If it cannot be identified by the cap color, it can be identified by tracing the low pressure line that connects the evaporator to the compressor.

2)    Start the engine and set A/C dashboard controls to max cooling.

3)    Remove blue cap from service port. Connect the pressure gauge to the low pressure service port through the connecting hose. If the gauge reading is below 25 psi the A/C needs to be charged.

A/C charge procedure

4)    Attach the dispensing device to the threaded area on top of the can containing the recharging gas.

5)    Attach the dispensing device to the compressor's low pressure service port through the dispensing hose.

6)    Hold the can in upright position and start opening the valve of the dispensing device.

7)    When charging procedure is completed, close the valve of the dispensing device by turning the handle in clockwise position till stopped.

8)    Remove charging valve and hose from can empty and discard.

After the charge procedure, the A/C should be checked again for the operative pressure (steps 1 to 3). If the operative pressure is not reached the A/C charge procedure should be repeated.

The A/C is fully loaded when:
1)    The gauge reading shows a pressure between 25 and 45 psi.
2)    The dryer shows the floating ball centered in the reading window.

A/C operative temperature check.

Place a thermometer on the main vent opening in the car dashboard. Turn on the A/C at max cooling.
After 5 minutes the thermometer reading should be between 45 and 60 F.

Charging tips:

It is important to not overcharge the A./C system. Refrigerant should not be added when the gauge reading is more than 45 psi. The total capacity of the A/C is about 25 oz therefore no more than 2 cans should be used.
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Comments and Suggestions:
Perk Comments: Upgrading my '80 930 to R134. Capacity is 47 oz R12; maybe 37 oz R134. Drained oil from Nippondenso and added 2 oz compatible oil. Rotated compressor about 20x. Changed receiver/drier and added 0.4 oz. oil. Vacuum for 2 hr. and shut down. 1/2 hr with steady reading -29 psi. Added Freon from 12 oz can, started motor and A/C at max. Can wouldn't empty. Low side reads 75 psi, hi side 5 psi. Needles not vibrating. Compressor runs full time. Compressor problem?
April 11, 2016
  Followup from the Pelican Staff: Sounds more like a restriction in the system. Low side too high and high side too low. - Nick at Pelican Parts  
Chris Comments: Have a 2001 Carrera, AC was nice and cold a trip out of town. Car was off for a couple hours, started it up and it was not blowing cold at all. Compressor is coming on and staying on as it should when I turn the AC on, thought for some possible reason the freon got low but when we put the gauge on high side it maxed the gauge out to bring the need back under the needle stop for 0 . Released some pressure to see what would happen, pressure came back up again, released pressure again to get it to the green and see if it would cool off but pressure risen again, pressed the gas and raised quick and maxed out. I do hear a condenser cooling fan on, not sure if there is one or 2. Any Ideas? Thanks in advance
September 23, 2015
  Followup from the Pelican Staff: Likely a restriction in the system. maybe in the expansion valve or condenser. - Nick at Pelican Parts  
Patrick Comments: So my 2004 911 TT cab had been running just fine but about 2 weeks ago I started smelling a "dead chipmunk" scent in the car and then this AM I only get warm air thru vents and no A/C. The fans are working but when I press A/C I hear laboring of fan/compressor and no cool air. How do you recommend I fix?
September 4, 2015
  Followup from the Pelican Staff: If the blower motor is noisy, i would remove it and inspect the heater housing. There may be rodent damage. - Nick at Pelican Parts  
76M2002 Comments: I'm confused about the ports. In the picture above in answer to jfk's post, it looks like the high-side port is attached to the upper manifold that is fed from the evaporator at the front of the car. I thought the right-angle fitting from the low port sends compressed gas to the condenser in the tail, and from there up to the front of the car. I'm working on a friend's '86 Carrera which looks just like this, but with the low and high side ports swapped for the logic above, and it won't charge correctly. So I suspect your picture is correct, I just can't figure out why.
August 2, 2014
  Followup from the Pelican Staff: Our photo is correct. - Nick at Pelican Parts  
WT Comments: I have an 82 911SC with the condenser in the whale tail and second condenser in nose. Not too many people are agreeing on the system capacity using R-134A.

Also I've seen ranges of low side psig ranging from 25 psig to almost 50 which seems way too high. My correction chart indicates around 26 degF.

I'm at a total loss here. Any info?
July 19, 2014
  Followup from the Pelican Staff: I would check with a retrifitter. There is usually a chart for your vehicle that will give a charge amount. - Nick at Pelican Parts  
Big D Comments: Have a 1980 911SC. When purchased 2 years ago, the A/C blew cold for a few minutes then warmed up... now isn't cold at all. So, classic case of needing a recharge, I think. In all of the many records from previous owners, there is little mention of A/C and no mention of the type of refrigerant. How can I tell what refrigerant is required?
July 17, 2014
  Followup from the Pelican Staff: You will have to use an refrigerant identifier (machine) to be sure what it is. - Nick at Pelican Parts  
robert Comments: my low pressure valve cap blue been missing for long time,does that matter? The evaporator coil was repaired welding for leaks.I used Enviro-Care 12A canada label said for replacement of HFC 134A &CFC-12.So far 6 yrs now,never work,would that be the drying agent just behind the driver side front wheel need to be replaced. Thanks
November 14, 2013
  Followup from the Pelican Staff: Not sure I follow the question, also don't know what type of vehicle you have. First, you need the low side cap, install one asap. The receiver dryer should be replaced when repairing leaks. - Nick at Pelican Parts  
RICK Comments: thanks kerry ,,it was the horn that was bad ,,you guys rock !
August 11, 2013
  Followup from the Pelican Staff: Glad to help - Kerry at Pelican Parts  
rick Comments: WHEN I PRESS THE HORN I ONLY GET A CLICKING ,,,ANY HELP WOULD BE THANKFULL ,,RICK
July 30, 2013
  Followup from the Pelican Staff: Where is the clicking coming from? If it's coming from a relay you may have a blow fuse, bad horn or broken wiring. Jump the horn relay and see if it sounds - Kerry at Pelican Parts  
RICK Comments: IT SEEMS IMPOSSIBLE TO BE ABLE TO GET IN THE 81 911 TO FIT ON A AC RECHARGE THERE IS JUST NO ROOM TO WORK ,,,,,ANY HINTS ,,THANKS
July 24, 2013
  Followup from the Pelican Staff: It is a tight fit. Assuming you are using R134 adpaters, they reduce the work space a bit, but do not restrict it. Which side are you having trouble accessing? Low or High - Nick at Pelican Parts  
rick Comments: thanks for all the help .
July 16, 2013
  Followup from the Pelican Staff: Your welcome - Nick at Pelican Parts  
RICK Comments: I HAVE A 81 ....911.....WILL TODAYS AC HOOK UPS FIT ON MY VALVE.
July 12, 2013
  Followup from the Pelican Staff: No you have to install and R134 retrofit kit - Nick at Pelican Parts  
Brian Comments: Is the update for the 996 out? Summer time is here and I got to check mine out.
June 17, 2013
  Followup from the Pelican Staff: Not sure I know what update you are referring to. - Nick at Pelican Parts  
stroke Comments: According to the Porsche Workshop Manual, a proper charge on a 964 using R134a should read between 10-15 psi on the low pressure port.
January 27, 2012
  Followup from the Pelican Staff: Thanks for the additional Info. We appreciate it. - Nick at Pelican Parts  
RSnead Comments: What is your recommendation/procedure to recharge the refrigerant in a 1999 - 911? Thanks! RSnead
December 6, 2011
  Followup from the Pelican Staff: Use the recommended R134 refrigerant and be sure to check the system for leaks before recharging. If you are unsure of how to do it, consult a professional mechanic. - Nick at Pelican Parts  
Geo Comments: I have an 88 Targa and the a/c blower works but no cold air. If I use the r-134 do I have to change anything?
July 25, 2011
  Followup from the Pelican Staff: The oil and charge amount will change. You can find this information with the people that sell the R134 retrofit kits. - Nick at Pelican Parts  
jfk Comments: I have a 1988 911 and both ports on the compressor appear identical. How do I isolate the low side port?
October 11, 2010
  Followup from the Pelican Staff: This photo should help. - Nick at Pelican Parts
Clay Comments: I need to recharge the refrigerant in my 1980 Porsche 911 SC.
What type of refrigerant do I need and how is it installed.
July 30, 2010
  Followup from the Pelican Staff: Those cars used R12, which is no longer available anymore. You might be forced to upgrade to R134, which is not a pleasant or cheap prospect. - Wayne at Pelican Parts  
cadman Comments: Oops wrong uploaded photo. Sorry guys.
June 29, 2010
  Followup from the Pelican Staff: No problem, thanks for the follow up. - Nick at Pelican Parts  
cadman Comments: Chuck or Wayne, I've removed the protective cap, is this the valve I turn clockwise prior to charging? Picture attached.
June 29, 2010
  Followup from the Pelican Staff: I believe so, although I'm not 100% sure from this photo. - Wayne at Pelican Parts  
chuck Comments: The service valve on my 80 911sc is located just above the low pressure service fitting on the right side of the big square York compressor. It is a square post type valve that sticks about an inch out of the compressor. It opens clockwise for service. I just recharged and have 40 degrees F at vent. Will see how long charge lasts....Chuck
June 15, 2010
  Followup from the Pelican Staff: Thanks for the follow up. We appreciate it. - Nick at Pelican Parts  
cadman Comments: Wayne, I'm referring to Chuck's 1980 911SC. I have a 1978 911 targa, I'm assuming that it has the same a/c service valve.
June 12, 2010
  Followup from the Pelican Staff: Originally, on a 911 SC, in the right rear of the engine compartment is the York (large square) A/C Compressor. On the right side of the compressor in conjunction with the A/C hoses and service fittings are the service valves. Once the A/C pressure gauge service hoses are connected, the “service valves” can be turned clockwise to allow the A/C service to commence.
- Tony Callas
Callas Rennsport Porsche BMW
Tele 310-370-7038
http://www.callasrennsport.com
 
cadman Comments: Chuck, could you be more specific as to where the service valve is located or possibly upload a pic?
June 10, 2010
  Followup from the Pelican Staff: For which car? - Wayne at Pelican Parts  
Chuck Comments: Have a 1980 911SC. AC was converted to R134 system. Have the original, believe York compressor. Is there a valve on the low side preesure fitting that needs to be opened to allow refrigerant in after attaching the fill hose to the fitting? When I open refrigerant can hose valve it seems no refrigerant is entering the system.
January 10, 2010
  Followup from the Pelican Staff: Chuck figured it out. There is a service valve that needs to be opened to charge system. Opens clockwise. - Nick at Pelican Parts  
AutoDad Comments: Have a 86 944 Turbo. Two questions. 1. Fan switch settings 1-3 do not work. Setting 4 does. Fuses are good but do not know how to check relays, my guess is a AA battery and a voltmeter, or listen for click? 2. Compressor kicks on and car stumbles, that's a new one for me. Is that a binding compressor rotor? Thanks, Dean
January 2, 2010
  Followup from the Pelican Staff: The fan switch issue sounds like the blower resistor is faulty.

if the compressor load is too high, it could be binding, or your idle might not be increasing to accomidate the load. - Nick at Pelican Parts
 
Mike Comments: Have a 2004 Carrera...looked under the hood and cant find any service port for the Air Cond....I see the AC hoses but cannot visualty follow them to locate where to attach the AC recharge. Would you know where it is and how to access it??? Thanks, Mike
June 25, 2009
  Followup from the Pelican Staff: The 996 is a bit different than the other earlier 911s. I will have an article coming out on this in the very near future. - Wayne at Pelican Parts  

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