Aircon suspected over filling with gas
 

Hi again.
It's only been my third post after a long absence, and here I am asking for advice and a little insight and guidance. Last week i took my 75 in to my local garage to get the air con regassed. The poor old owner has been really ill of late suffer from cancer and has been closed for quite a while whilst fighting this awful disease. I thought i would put some business his way with an easy light job and asked if he could re gas the air con. As the car is 20 year old i went into this with an open mind. There could be any number of things wrong which I would accept, but a couple of hours later I got the call to say its all good. There was no leaks and everything was working fine.
Driving it home i did however notice it wasn't as cold as it used to be a few years back. It just didn't have that bite. I just put it down to either me kidding myself or that it was because it was exceptionally hot. Two days went by and the air con has stopped working. I can hear the pump clicking in and the engine taking the load but it's not producing any cold air. I was a bit reluctant to take it back to the garage, as he's really not very well and i don't want to burden or pester him whilst his so frail.
Incidentally the pump/compressor now sounds noisy and it's got me thinking as it did sound like this once before when the system was over filled with gas. Talking today to my next door neighbour who is a mechanic at a garage, he is sure it's been over filled by the symptoms I've told him. I've done him a few favours of late and he's going to check my car out tomorrow afternoon to see what's going on.
I thought I would ask here for you opinions here about it all. Maybe you could throw some more light on it all.
Thanks for reading and and the very best,
Johnny.

The gas should be put in by weight (the amount is quoted on the plate on the slam panel) so the only way you would know is to take it out and weigh how much is removed.

I have no idea what would happen if you did overfill, perhaps there would not be enough room in the system for the gas to expand sufficiently to remove the heat from the car interior?

Thanks for the reply. When i said the compressor is noisy, i think it's more like a sound that the belts are over tight that turn it. It only sounds like this when i engage the aircon. This strange sound appeared once before when it got overfilled. Obviously I'm no expert on such matters so I certainly report back tomorrow when it's been checked over

It depends on how much the system has been overfilled if it has been, I have seen vehicles that have been so overfilled that the compressor would not turn but if it was say 10 or even 15% overfilled I doubt you would notice. With the price of gas now it would surprise me if it had been.

An A/C specialist would be able to tell if it has been overfilled with some gauges, the pressures will be to high.

Are you sure it is not just a worn belt and?or pulley making a noise with the load?

It's an odd one .if you think the compressor is tripping in .
Maybe the noises where their before and now you are listening more . Sorry don't want to patronise .
Is the fan switching on and off .
In all fairness the chances are the condenser is corroded and leaked with the pressure of the re gass . Look through the grill and see if it's corroded . I changed the lot last year after a failed re gas.
Condenser failed . . New radiator while it was in bits .

Hi again. I did promise an update yesterday, but after having my second jab on Tuesday I ended up going straight to bed yesterday right after work feeling rough, and didn't take the car over to the neighbours garage for some investigations on the aircon issue. Still feeling under the weather with a splitting headache and aching limbs, but sure a few paracetamol will get me through the day today.
As you say it is a strange one. The system was pressure test and i can definitely still hear the compressor kicking in and the rad fan seems to be all working as it should. When the compressor kicks in, it does sound (to me) like the belt driving it is either under a great strain and sounds like it's over tensioned. The last time i had this issue it was down to the aircon system being over filled. There's obviously a lot more involved to all the workings of the aircon system and my limited knowledge maybe barking up the wrong tree. All being well the garage will have time this afternoon to take a look and give me an answer. Coming home yesterday it was like an oven in the car, and feeling the affects of the second Covid jab, i was sweating like a pig, so hopefully it will be a simple straightforward fix of (famous last words) of a simple re gas of the correct amount :=))

Hello John,

Overfilling with refrigerant is the least likely reason for the lack of cooling. Your condenser may be inefficient due to corroded fins and/or the refrigerant gas may be leaking out through dry seals. The good news is that your compressor is engaging. I wouldn't worry too much about the noise at the moment. That can be the result of a low charge.

What you need to do is to use an air conditioning specialist, either with premises (rare these days) or a mobile self employed person. They will not just recharge the system but use everything at their disposal to check your system thoroughly. If you're anywhere near Colwyn Bay, forum member Jules offers air conditioning services and specialises in the 75/ZT.

Simon

You need to take your car to an air conditioning specialist, one who actually knows what they are doing, who would explain the entire process to you whilst it is carried out.
The chances are the condenser is missing 50% of its cooling fins, you cant see this until it is removed from the vehicle, then the gas needs to be removed and weighed then adjusted before adding it back into a fully well evacuated system, together with specialist oil to lube the compressor and the seals, these need to be replaced as needed.

The system then needs to be ran to check for leaks (UV dye added), and that it actually cools the interior of system as intended, then you pay the guy and go on your way, a happy chap/chapess!.

Hi, just a quick update.
Well it's turned out the condenser is leaking. The other garage gave the aircon system a good checking over and discovered it to be leaking. That's another job on the list to tick off. I'm a bit confused as to, when I had it re gassed the other week, i was told by the other garage it was all good and there was no leaks, only for it to fail a few days later. As said before I'm reluctant to take it back and complain as the garage owner who did it, is really not in the best of health and looks really frail. I just don't want to cause him any undue stress or aggro over what's essentially just a piece of metal. Plus it could be just coincidental it's failed when it did.
So I'm going to right this off to experience and just get it sorted out at another garage. Its not a desperate /vital part of the car that needs fixing to keep me on the road, but non the less i would like to get it sorted sooner than later.
Many thanks for all the help and support given, and to be fair you guys here, diagnosed the problem without even looking at my car.
All the best to you all.

Hi John and thanks very much for the update. I'm glad that it's good news and easily repairable.
They may have relied upon the system holding a vacuum as proof that there were no leaks. I found out by experience a few years ago that this is not the case! :eek: A nitrogen gas pressure test is a far more reliable method and only the air conditioning specialists will have the equipment to do that.
I'm sure that everyone who contributed to your thread will be very pleased to read this. Sometimes we give advice and the original poster never returns to say anything!

Simon