Air Conditioning Investigations

So, we decided to go out for a short trip now that the Coronavirus lockdown has been eased a little and it was a beautiful sunny day. We set off with no particular destination in mind just a ride out for a change of scenery, we don’t think it is fair yet to descend on the local beauty spots where people who live there have also been in lockdown.

As I said it was a nice sunny day with temperatures in the low 20’s C so on went the Air Conditioning. Having travelled about 15-20 miles we both said “it’s a bit warm in here” and on checking, the Aircon wasn’t working. We decided to return and came back with the windows down !!!

I have quite a good setup in the garage with just about any tool I might need for doing a job as some of you might have seen in my previous Blogs, what I don’t have however is Aircon testing and gassing equipment, who does !!!

Anyway, I jumped on the internet to find a mobile guy near us to come and do a few checks. As it happens my wife’s Audi had a problem as well so I thought we could kill two birds with one stone. The first guy I rang asked me what the cars were, I told him an Audi A6  S-line 3.0ltr TFSI and the second car an Aston Martin DB9. There was then a pregnant pause and I could imagine the money signs in his eyes🤑! He came back with “I could do them both for only £465.00”. After a deep gulp I said I’d get back to him if I was interested but at that price I said, I think I’ll just be opening the windows !!!

My next call was to “Car Aircon Services” http://carairconservices.co.uk/ and I spoke with Damian. He covers Manchester and North Cheshire. All his prices were set out on his website, no hidden extras, he told me when he could come and even arrived an hour early. As soon as he started to look at the cars, I thought this guy knows what he’s doing. You just get that soft and squeezy feel about it. The Audi was resolved within a few minutes of checking gas pressures and connecting up his ODBII reader, a faulty pressure switch, for which he carried OEM parts in his van.

So, to the Aston, this is a story of woe I’m afraid at the moment. A check revealed no gas in the system. Moreover, we discussed the background to the car and we (well Damien) came to the conclusion as you will read.

Arrangement of Air Conditioning System DB9

Drive belt arrangement for A/C compressor drive and other items

I bought the car just over three years ago from a dealer in Wimbledon, South London and he undertook to carry out an oil change service prior to me collecting it a week later. Part way through the week I received a call saying that the air conditioning had stopped working and they would need another week to get it sorted. No problem I thought better to be sorted now than have a problem later.

When I collected the Aston, everything was perfect and as we drove back up to Manchester (about 31/2 hours just over 220 miles from the dealership for those who are not aware) the Aircon was working fine. However about 3 months later the aircon stopped working so I gave the dealer a ring and he said bring the car back and he would get it sorted again. After some discussion about the distance involved and me having to make two return trips to London and associated costs, he agreed for me to get it tested locally. I found a local mobile guy (not Damien at the time) who came and checked it out but he concluded that there were leaks from both the condenser radiator and the compressor. I relayed this to the dealer who was quite sceptical at first when I told him it needed a new condenser radiator and a compressor plus fitting of same. Eventually he agreed as long as he could supply the parts and my guy could fit them. A few days later an OEM condenser radiator arrived at the house direct from Aston followed by a “reconditioned” compressor from another company. These were duly fitted by the guy I was using at the time and the system re-gassed.  

Aston Martin DB9 – Refrigeration System

All was then OK for the next 21/2 years or so, until now. Damien found traces of dye under Ultra Violet on the connections to the new condenser radiator but he concluded that this was dried residue from when the condenser was fitted. More serious he found evidence of fresh dye around the pulley drive end of the compressor. Damien suggested that even though the compressor was a reconditioned unit it should last a good number of years certainly more than 2-3 years.

Damien put forward a hypothesis with which I am inclined to agree. He has seen it before that a leaking system is repaired with a sealant additive. This works in the short term, however it is only a temporary repair, moreover it can lead to more problems. It is possible that the dealer in London might have had the original leak repaired by the use of such an additive. It follows that this repair would then fail after a short time, perhaps shorter than he would have expected and he then had to provide new replacement items under the 6 month warranty.

Unfortunately, once the sealant is in the system it is near impossible to remove, it requires complete flushing and possible replacement of other parts of the system. The sealant can blind pipes and galleries along with the other items in the system such as the expansion valve, receiver drier or the accumulator this causes the compressor to run at higher pressures to maintain circulation ultimately this higher pressure weakens seals in the compressor and produces the leakage trace usually at its drive/pulley end.

Expansion Valve comparison with sealant contamination
Damaged compressor shaft seal with sealant present

For now, we are in the testing period as Damien has refilled the system with gas at my request and we will see how long the Air Con keeps working. The result will determine the path forward but now the leak is established I suspect it will not be long before I have another Blog to post on changing the Air Con compressor or even more items !!!

A quick search on the internet found quite a few of these products on the market all professing to seal your system leaks, but none advise of the potential pitfalls. I found an article on line that confirms everything that Damien told me, you can read it by copying and pasting the link, if it doesn’t work don’t ask me what do I know, I found through Google so good luck !!!                                            http://www.ricksfreeautorepairservice.com/does-ac-stop-leak-sealer-work/

There is a short video of the preparations for the investigations and some commentary on the results. See    https://youtu.be/e6nYb2IMbQE

My recommendation would be to bite the bullet on your air conditioning and get someone in like Damien who knows what they are doing and don’t go for short term fixes, it could end up costing you a lot more in the long term. Watch this space over the next few months (or perhaps days !!!) for progress updates.

By the way Damien’s price for both cars one with a new pressure switch and the DB9 checked out and regassed not to mention his advice (he was here for over 2 hours) was £134.00, more than reasonable.

Mike (Aston 2209)

One thought on “Air Conditioning Investigations

  1. Mike many thanks for sharing this. Very interesting to note. My car touch wood is ok, but found the information very useful to say the least. Hope all goes well as I know repairs are expensive. You are lucky to have a decent and knowledgeable ac guy locally.

    Like

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