Air Conditioning Service
An inexpensive solution?
After purchasing my 1990 3.6 litre XJ-S in 2002, I understood that one day soon I would have to address the potentially expensive solution to the age old problem that the air conditioning system was just not performing as it should, it was not delivering cold air and therefore the climate control system was not functioning correctly. I had already read in the JEC magazine that the system was a complex piece of Jaguar engineering and that any problem was likely to be a very expensive rectification exercise, not being one who is beaten easily I set out to try and un-fathom the dark secrets of the system which in this model is the Delanair Mk 3 system. Earlier Jaguars were fitted with the Mk 2 system which operates exactly the same but has an amplifier control system as opposed to the later electronic temperature control unit.
I had researched the system in the workshop manual and later on the CD Rom supplied by Jaguar/Daimler heritage and felt I was beginning to understand the operation a little better. Information on the Web gave me a test procedure to enable me evaluate the function of all controls and to determine if all heater flaps and vacuum controls were operating correctly. Once satisfied that all was basically well with the system I eventually decided to speak with the JEC technical guru David Marks who pointed out that the electric cooling fan in front of the condenser, which is situated in front of the vehicles radiator and "never works", needed to be somehow rewired to make it operate in conjunction with the switching on of the air conditioning system. After studying the vehicles wiring diagram I found that this fan is designed to operate only when the main radiator/engine temperature rises to a specified point and is activated by a thermal switch in the vehicles radiator. Not to say that the system might be more efficient if this fan did operate all the time, I was not convinced. Back to square one grumble grumble!.
When I purchased the car, the air conditioner compressor operated as it should, engaging when switching on the interior heater/demist fan, and this is where I was mislead. On further investigation in August 2003 I found that the compressor was no longer engaging so I was now convinced that either the compressor was faulty or a thermal safety fuse had blown thus stopping the supply of electrical power to the compressor as described in my version of the workshop manual. Not so, I had power so decided to price a re-conditioned compressor and while I was at it, a new system condenser, and a new receiver dryer all at a cost of around £350 however to enable me do the job legally, I had to get the system gas (R12) removed by an approved Air Conditioning expert. Now I was really getting involved but alas who could I go to locally? Looking in the yellow pages and on the internet I was only able to find a few local garages in Carlisle and Penrith and a national firm with a depot in Dumfries. The latter seemed a long way to travel just to have the gas removed and the local garages were not that interested and bombarded me with technical questions giving me the impression that they did not really want to work on a Jaguar. Looking again more closely in the Yellow Pages I noticed an advert for "Arctic Air Cumbria Ltd" in Low Moresby near Whitehaven just 4 miles from my home. A short phone call and an enlightening conversation told me that the most likely cause of my trouble was a pressure overload switch in the system which is designed to protect and isolate the compressor in the event of either too low or too high gas pressures.
I duly made an appointment and Michael Reaney tested the system before pronouncing that it appeared to be short of gas and that he would evacuate the system and weigh the amount of refrigerant gas left in the system and then test for possible leakage. Around 1.2 pounds of refrigerant was removed from the system and the information he had said that it should hold around 2.5 pounds of refrigerant gas. He then pressurized the system to 160psi with nitrogen gas and used a very sensitive test probe to check for leaks both inside and outside the car and at all pipe work, components and connections, all areas passed the critical test which is believe it or not 0.05kg in 40 years permissible leakage. By now I was getting good vibes and the repair cost was reducing by the minute. He then put the system under a sustained vacuum for around 30 minutes before adding the replacement and legal refrigerant known as RS24. It is worth pointing out that the modern gas R134A is not compatible with the older systems and to avoid contamination of compressor lubricant and rapid deterioration of hoses and seals, a substitute gas such as RS24 needs to be used.
After loading the system up with the required 2.5 pounds of refrigerant, the moment of truth had arrived. Switching the system on activated the compressor clutch, so far so good, it worked and turning the controls to cold brought a gush of lovely cold air from the vents. All this was for a cost of £70 and has saved me a packet. Yes I hear you saying, why did he not just get the system gassed up sooner? Well I believed there was adequate pressure in the system and had been convinced by others that I would be up for a major system overhaul. Talks of thermal fuses and non operating electric fans had not helped either. Working the system out for myself has given me a better insight into just how this complex system operates and I fell better for that knowledge. Furthermore I have found a service that could benefit many of our club members if in fact they want their Air Con systems checked and regassed. Michael Reaney is a very approachable guy and knows his stuff; and as a bonus he is willing to do the work either on site or at his home.
Conclusion. If club members wish to use the services of Arctic Air then maybe a few cars at one location would make an on site session more viable if this could be of interest then ask me about the prospect and I am willing to organize this with Michael Reaney. Think about it as a project before the start of our summer in 2004. Air conditioning does need to be serviced at roughly 2 year intervals.
Arctic Air Cumbria can be contacted on 01946 696 310 or mobile 07732 917 620
Further to writing this article a club member has indicated that as part of his business he too services automotive air conditioning. For further details contact -:
Murray Gibson (Club member and self confessed Jaguar nut) in Carlisle on Tel. 01228 595 277 (workshop) or Email, murray@gibsonservices.idps.co.uk
Col Murray