May be that the system needs topping up (should be able to see the refrigerant fluid through the window according to the Handbook - but I can't!) but the old fluid is difficult to get, and the new, more environmentally friendly fluid may require some changes to your A/C system. As likely, your condenser / dryer may need to be flushed out as well as re-charging the system. Probably a specialist Job (see Contacts List) - Andrew S, Rob F

A/C in the South East. London United Engineering Ltd in SW19 (South Wimbledon) 020-8540-0075. Very knowledgeable & efficient (£105 incl adding oil & a dye in the R12 gas for lubrication & leak detection). Parr Garage at South Godstone & AFN at Guildford have both "re-gassed" it once, neither of which lasted longer than 2 or 3 months each time!! - Dave B

an interesting web site, with good graphics, that explains how a/c works etc. www.autoclimate.com Regards, Phil R

944 - Don't go by the sight glass any more when filling your a/c system, you will have way too much R134a in it. It calls for 85% of what a full charge of R12 would be. Look in the manual and use that figure. A good high would be 175 at 1500 rpm and low maybe 25 at same., be sure the fan works! This system will leak more than the R12 did because the 134 will pass thru that old hose easier than R12 did, and it will never get as cold as is did before. Roger - 19th June, 2001

964 - Sounds like you have got a leak. Most likely to be the condenser situated under the LHS front wing. These tend to corrode due to being exposed to all the elements. I had the same problem with mine and had it replaced for aprox GBP400. The part is aprox GBP250 then add labour and gas. The compressor is GBP1000!!! but they are very robust and unlikely to fail. If it has either find one s/h or get one form the USA - contact me for details. I had the work done at Arlington, mention your Club membership and get 10% off parts and labour. BTW: Arlington has a new parts guy now (Ted Craig) who is a LOT better than the old guy. Alternatively try Automotive Cooling Services 01604 639005 They are an independent air con specialist but they buy their Porsche parts from Arlington so you will only save on labour - Steve W - 26th June, 2001

964 - Yesterday I had my system recharged, and it was still found to be ineffective bowing 36 degrees C through the main vents. It turned out that the condenser fan was not working. On a whim I thought I'd check the fuse which was blown. (probably blew when driving through a flood earlier this year - the condenser being very low and right at the front of the car) Its now nice and coooll - Mike Q - 27th June, 2001

go to a specialist, have them remove the R12 and regas with a drop in replacement (this means nothing to change but the gas) and make sure they add the dye. Just done this on my 90 C4, cost £40, now I have a legal gas and can see the leaks! Any one who says you must change all the seals and components is just either A: following advice from Porsche who state change the whole system and regas (so that is what an OPC will do) or b: ripping you off by just adding a drop in gas and charging you for more (got a quote like this from one, so called specialist, without seeing the car he said 2 yep £400 plus labour and gas, takes us 2 days) actually took 1 hour and £40! - p.s I now have a leak, but at least I can see it under the ultra violet light! - Keith R - 28th June, 2001

Although R12 gas is now illegal there is no requirement to change it for the approved gas. However if you have a leak on your system or require any work which involves recharging the system the dealer will only use the new gas. I have been told this involves a conversion and the addition of a dye to show up leaks, if any. I have been quoted £135 plus VAT by a specialist in Birmingham. The cost of curing any leaks would be in addition. Roy B - 28th June, 2001

My understanding is you do not have to change the gas and you are allowed to extract it and clean it and reinstall it but you can not top it up. Mike Q 28th June, 2001

2nd July, 2001 - Seeing as there have been quite a few questions on aircon lately, here is some text for those who wish to remove the R12 and replace it with something more environmentaly friendly. Applies to all pre model year 1993 Porsches.
911C4 Climate Control System-Refrigerant 134a Use Model Year: Up to 1992 - Use of refrigerant substitutes. (sometimes referred to as "drop-in's")
In the interest of protecting the ozone layer, the manufacturing of refrigerant type R12 has not been permitted since January 1, 1996. As a replacement for refrigerant R12, most manufacturers, including Porsche, have required the use of refrigerant type R134a. This applies to new vehicles (as of 1993), as well as existing vehicles originally equipped with type R12 climate control systems.
In spite of the R12 restrictions, there are products being developed and sold in the after market as R12 substitutes, or "drop-in's". These products have NOT been tested for compatibility with Porsche vehicles, and therefore ARE NOT APPROVED by Porsche. The only approved replacement for refrigerant type R12 on Porsche vehicles is refrigerant type R134a.
Please refer to Technical Bulletin Group 8, number 9501 when retrofitting a Porsche climate control system from refrigerant R12 to refrigerant R134a.
"Drop-in" refrigerant R12 substitutes are not approved for use in Porsche vehicles. Any damage or failure resulting from the use of these "drop-in's" will not be considered a warranty matter. - Adrian S

5th July, 2001 - I am looking into this thoroughly at the moment as I appear to have a leaking condensor. Costs quoted by Arlington for replacing condensor AND dryer (recommended to to both at same time) Recharge with inert gas & dye (to verify leak is coming from condensor) £70 + vat Labour £160* + vat Condensor £240* + vat Dryer £135* + vat Recharge with R134a £110 + vat * less 10% for PCGB JZ Machtech quoted £500 + vat for whole job (including replacement of a "resistor" which they said always needed replacing when this job is done). This seems cheap, but unfortunately they are too far away from me to make this practical. I was told by a local guy (who said he knows Porsches as he used to work for Chariots) that the dryer is a standard Parker dryer and can be bought non Porsche branded for around £50 - £60. He also said he can to a R134a recharge for around £85 with no VAT as he is not VAT registered. He also stated that refilling with R134a is a temporary solution as this, like R12 will be made illegal within 2-3 years. He advised that the system could be converted to the latest gas by replacing seals etc in the system for an additional cost of around £200. His contact info is 07730 495928. As I am going to Germany on business next week I rang up the local OPC and priced up the above parts. It would seem that the condensor and dryer can be bought for a total cost of £270 (DM853), so I plan to buy them over there and then have them fitted by a local specialist (probably Bob Watson). With the recharge this would work out around £540 inc the dreaded tax. This will save around £250 - £300 on the Arlington price. I am also planning to buy the rear central light assembly (curiously they have a UK spec one in stock) and save around £80 - £100 on this one item alone. - Doug C

5th July, 2001 - Just spoke to Polar Refrigeration to get some clarification. R134a is the NEW gas that requires a system conversion. There is a blend gas that can be used (subject to Porsche not approving it - see below) which is basically R134a with isobutane in it, to drive the oil around the system. Now I'm in a quandry about what I should be doing in oder to get the job done properly - Doug C