The air con on my 05 plate bkd octavia has packed up. I had it looked at today, and there is a leak from where one of the pipes, the thinner of the two, bolts on to the top of the compressor, the bolt is a sort of figure of eight shape, and the pipe runs down the way and then under the compressor. Can anyone advise if there is an O ring in that connector which might have failed, and advise of a part number for same, and also the part number for this bit of pipe also in case I need to replace it. Thankyou in advance.

Both the pipes have o-rings on them to make the seal. You can get these easily and the job of changing them is simple but a bit awkward. You will need a hex bit the get the bolts out, once out pull the pipe directly up.

The seals must be lubricated with PAG oil on assembly. The system will then have to be leak tested before filling.

Thankyou. I can see the hex nut, it is pretty rusty, best bet then will be to source and change the o ring as described (thankyou for the oil advice) then try to regas again and take it from there. Will visit skoda for o ring tomorrow.

It will need to be leak tested to verify the leak is sorted before it can be gased with R134a.

Yes got that. Replace o ring. Leak test hopefully no issues. Regas. Thankyou.

Nuisance. Got the o ring, cost a quid, fitted it, leak test again. Guess what. It appears the leak wasn't from that connection. It was from the pressure sensor plug in thing right next to it. Have read previous threads that this is a weak point. Is it the sensor itself that usually needs replaced or the pipe that it connects in to??

Sounds like the same as what happened to mine. Thought it was the 'stalk' (off the main pipe) that the pressure sensor sits on that was cracked but when disconnecting the plug you could see the green dye of the refridgerant actually inside the plug. You can buy the pipe 2nd hand but I went new route and you can only get 'genuine'. Mate who has his own garage got one sent from TPS and it was £190, when I went to get it fitted I could see they had sent the wrong pipe. That was OK I thought as the actual pipe needed was about 1/3 of the length of the one they had sent so it would be cheaper. Oh no thought it was actually more expensive but because they (TPS) had messed up they sent the correct one for the same price. Pt number of the pipe for my VRS was 1KO 820 721 BN. Google it and see if that's the same pipe you ned.

Edited 22 June, 201610 yr by hatchy

Thats a really helpful part number thanks. Going to have another look at it today see if I can work out whether I need the sensor or the pipe or both.