Aircon compressor fix
Posted: Sat Jul 11, 2015 8:42 am
Thought I but together a guide for those who have a problem with their aircon and a possible cause and solution that won't cost the earth to fix. This is a little bit of a ramble as it goes through the whole process but the key is that if you have the same issue I did you can skip several steps and save yourself some money.
Starting at the beginning I noticed that the aircon wasn't getting cold anymore, very quick inspection showed nothing obviously wrong, so my first thoughts were it just needed a quick re-gas.
Round to the local tyre store, quote of £39 to re-gas. An hour later they reported that the compressor was faulty and needed replacement. Estimated cost £600, £500 parts, £100 labour. They removed the gas and I departed without spending a penny, but 2hrs lost.
First Tip - Check with garage/tyre store if they charge anything if there is no improvement, most large chains won't charge you if they make no difference to your aircon.
So I got home and did a little more investigation, first thing I noticed was that the bolt in the end of the compressor (at the pulley/clutch) looked like it was sticking out and wasn't fully tightened. So first idea was to try and tighten this bolt....unfortunately this didn't work. The problem was that the bolt would just turn and would not tighten. The pulley or clutch weren't moving what I eventually found out was happening was that the internal shaft of the compressor was turning as I tried to tighten the bolt. I couldn't see anyway to hold the shaft still to allow it to tighten. I will explain why later....
The later compressors used on VW's don't have the old magnet clutches anymore, the pulley is permanently connected through a clutch (more or a spring damper) to the compressor shaft. I assume that the clutch is sacrificial if something jams and is designed to break or give way.
My diagnosis was that the compressor needed to be replaced.
Second Tip - check your compressor to make sure the clutch bolt is not coming loose
After a couple of days searching and bidding on ebay I found a second hand compressor for a great price, so I bought it.
As I'd already had the gas removed (free of charge) by the garage I decided I could dismantle the aircon system and get the compressor off and replace it. Simple enough job:
- lift front of car
- remove under tray
- remove fan belt
- disconnect control cable
- depressurize system by pressing valve (ONLY DO THIS IS YOU HAVE HAD THE GAS REMOVED)
- remove charge cooler pipe (makes access easier)
- remove 2 aircon pipes
- remove fixing bots x3
- extract compressor
Removed.....now this is where it went a little wrong...turns out the compressor I bought was the wrong one!!
Whilst I had it off the car I decided to try and figure out why the bolt was loose and wouldn't tighten. It turns out that the problem was that the clutch splines has been stripped so that the clutch was no longer engaging with the compressor shaft.
The old clutch, if you look carefully you can't see any splines.
The compressor with the clutch removed
A close up showing the shaft splines - which were completely fine.
So now the challenge was to find if this part can be purchased, well the first thing to do was to put it all back together as the car is not drivable without it. So I reinstalled the compressor (without the clutch).
A quick search and I found a guy in Germany who sells the clutch assembly, on it's own, not the entire pulley, just the clutch. After paying the £40 which included delivery, I waited for the item to be delivered.
Third Tip - if you are trying to find second hand bits use ebay, but also try the German ebay site "ebay.de" its amazing what you can find.
New part arrives!! You can clearly see the splines in the centre of this
Now the installation, this time there isn't any need to dismantle or remove anything, all I need to do is drop the under tray off and work from under the car. 3 screws and 1 bolt later (remember to use thread lock) and its done!!
Final step for me is back to the garage for it to be re-gassed and now I have lovely cold air!!!!!
So I could have saved myself the cost of the regas as it wasn't the problem...so it would have only cost £40 and a couple of hours of work....still better than the £600 quoted originally.
Hope this is useful for someone.
Starting at the beginning I noticed that the aircon wasn't getting cold anymore, very quick inspection showed nothing obviously wrong, so my first thoughts were it just needed a quick re-gas.
Round to the local tyre store, quote of £39 to re-gas. An hour later they reported that the compressor was faulty and needed replacement. Estimated cost £600, £500 parts, £100 labour. They removed the gas and I departed without spending a penny, but 2hrs lost.
First Tip - Check with garage/tyre store if they charge anything if there is no improvement, most large chains won't charge you if they make no difference to your aircon.
So I got home and did a little more investigation, first thing I noticed was that the bolt in the end of the compressor (at the pulley/clutch) looked like it was sticking out and wasn't fully tightened. So first idea was to try and tighten this bolt....unfortunately this didn't work. The problem was that the bolt would just turn and would not tighten. The pulley or clutch weren't moving what I eventually found out was happening was that the internal shaft of the compressor was turning as I tried to tighten the bolt. I couldn't see anyway to hold the shaft still to allow it to tighten. I will explain why later....
The later compressors used on VW's don't have the old magnet clutches anymore, the pulley is permanently connected through a clutch (more or a spring damper) to the compressor shaft. I assume that the clutch is sacrificial if something jams and is designed to break or give way.
My diagnosis was that the compressor needed to be replaced.
Second Tip - check your compressor to make sure the clutch bolt is not coming loose
After a couple of days searching and bidding on ebay I found a second hand compressor for a great price, so I bought it.
As I'd already had the gas removed (free of charge) by the garage I decided I could dismantle the aircon system and get the compressor off and replace it. Simple enough job:
- lift front of car
- remove under tray
- remove fan belt
- disconnect control cable
- depressurize system by pressing valve (ONLY DO THIS IS YOU HAVE HAD THE GAS REMOVED)
- remove charge cooler pipe (makes access easier)
- remove 2 aircon pipes
- remove fixing bots x3
- extract compressor
Removed.....now this is where it went a little wrong...turns out the compressor I bought was the wrong one!!
Whilst I had it off the car I decided to try and figure out why the bolt was loose and wouldn't tighten. It turns out that the problem was that the clutch splines has been stripped so that the clutch was no longer engaging with the compressor shaft.
The old clutch, if you look carefully you can't see any splines.
The compressor with the clutch removed
A close up showing the shaft splines - which were completely fine.
So now the challenge was to find if this part can be purchased, well the first thing to do was to put it all back together as the car is not drivable without it. So I reinstalled the compressor (without the clutch).
A quick search and I found a guy in Germany who sells the clutch assembly, on it's own, not the entire pulley, just the clutch. After paying the £40 which included delivery, I waited for the item to be delivered.
Third Tip - if you are trying to find second hand bits use ebay, but also try the German ebay site "ebay.de" its amazing what you can find.
New part arrives!! You can clearly see the splines in the centre of this
Now the installation, this time there isn't any need to dismantle or remove anything, all I need to do is drop the under tray off and work from under the car. 3 screws and 1 bolt later (remember to use thread lock) and its done!!
Final step for me is back to the garage for it to be re-gassed and now I have lovely cold air!!!!!
So I could have saved myself the cost of the regas as it wasn't the problem...so it would have only cost £40 and a couple of hours of work....still better than the £600 quoted originally.
Hope this is useful for someone.
Now researching to find solutions/diagnosing help to hopefully save me some money if possible! 
. I had a similar problem with my aircon. Tried the recharge at a local garage no no avail. Similarly suggested a compressor replacement. I had a go this afternoon based on this thread and lo and behold I find my clutch spinning and no bolt. Removed it and just as above there are no splines.