Gentlemen
Finally managed to resolve the A/C regassing issue (for those that don't know, my beast is a pre-1993 3.8 ltr), and just in time too; the sun is shining and it's getting warmer!
Contacted a chap called David Fry who is an aircon specialist and runs his own mobile car aircon servicing business (
http://www.bee-cool-aircon.co.uk) in Northhamptonshire. He advised me that although the R12 refrigerant has been banned for the past 15 yrs, he is able to offer a 'retrofit' regassing service using the substitute RS24 refrigerant, which is virtually identical in composition to R12.
Seeing as I couldn't find anyone local who offers the same service as he was offering, I decided to drive up to Milton Keynes today to rendezvous with him at a service station outside the town.
Once he set up his equipment, he conducted three tests on the a/c system:
1. Initial Gauge Test - to determine if there was any refrigerant present.
2. 5 minutes Vaccuum Hold Test.
3. System Pressure Test (using O2 free Nitrogen) - to determine if there are any major leaks in the system.
After that, he did a 30 minutes Deep System Vaccuum and then added the mineral oil and RS24 refrigerant. Also, the drier unit was cleaned (he did mention that, ideally, it should be replaced) to 90% efficiency.
He then did a visual check to make sure the compressor was running okay and then took a before temperature reading (22.4 degrees C) at the vents and then another one (7.1 degrees C) 4 minutes after the a/c was switched on.
The whole process took about 80 minutes during which he was careful to explain - in words that I could understand - exactly what he was doing.
David really knows his 'onions' when it comes to aircon servicing and I don't think I have met anyone who showed as much enthusiasm for his craft as he does. He really did impress me; well worth the £129.00 spent.
On the way home, I ran the a/c for about 35 minutes. It was so cold, I could see the condensation on my breath - it must have been about 5 degrees C inside the cabin!
I can only add if any board members find themselves stuck with the same problem as I had, they contact David first (telephone number on his website) and listen to what he has to say. I hope this post will prove useful information to all.
I have just one more thing to say which might be of interest. David was pretty certain that this was the first time the a/c system has been regassed. That's 16 years since the car rolled out of Garching! Enough said.
Kurt