I've got a W reg Polo 6N2 1.4 (75).

The air con seems to make a really loud clicking noise when I turn it on and off.

Also, the engine runs not too bad at all (sometimes at junctions I can't even hear the engine!) but with the air con on, it's like there's a small earth quake. Everything shakes violently like the revs have dropped considerably although I can't see that they are?? On setting "1" it's quite bad, but turning it up to 4 causes unbearable shaking!

No idea whats going on - would appreciate any help, particularly from people who have experienced the same thing in a 6N2!

EDIT: Just found out the juddering/shaking can be caused by bad air compression/air flow? Like an air pipe somewhere leaking or cracks in valves??

My exhaust has been blowing a bit lately so I don't know if that could explain the juddering.

Still no idea about the loud click/tick noise when I turn air con on and off.

Edited 3 August, 201115 yr by bigukg

if the juddering only happens when the air con is on then it has nothing to do with your valves in the engine. its because the air con pump puts a load on the engine effectively sapping some energy making the engine a bit rougher at idle its a normal thing but not when its that extreme so something must be amiss with the air con pump.

no idea about the clicking.......

Thanks for that, I've got a horrible feeling that means pump aka compressor? Really don't want to have that replaced because they're so expensive.

Because I often use my air con when I sit in my (on breaks etc at work when it's too hot outside) I tried running it for a mile or so, then pulled over to see if the juddering was still there when I idled after a run, it was. Perhaps slightly less violent but bad all the same!!

My main concern is, can using the air con when it's doing this juddering thing do any damage to the engine etc due to belts?

The more I think about it, the more I think that clicking is the compressor going on and off, it's just so loud because it's fooked!

I'm not sure it would because if the belt snaps (assuming the belt for aircon only connects aircon pump to engine, not alternator etc) it would just be like not having aircon.

Thanks again, I'll try and find out - in the mean time if anyone knows whether the air con uses a dedicated belt or not!

EDIT: Duhhhh. Going to give the VW Service Dept a call and ask them, surely they can take the reg number and have a look. Might ask them about the problem too,

Edited 3 August, 201115 yr by bigukg

As an update; spoke to the service dept. at my local VW dealership today.

Remembered my fiancees friend works on the service desk, so I asked her a few questions and spoke to the manager!

The alternator belt drives the air con compressor, so I won't be using the air con for now until I know what's wrong. Won't risk the belt going.

They didn't say much about the clicking! But the juddering they said is normal to a point, but it might have got worse just because it needs re-gassing. It's either that or the clutch on the compressor they reckon.

Air con re-gas and inspection is £80 and MOT is £39!

sounds like the clutch on the compressor failing. i wouldn't recommend using it, seen a couple melt parts and 1 catch fire.

Thanks - deffo won't be using it then!

Can the clutch on the compressor be replaced without having the lot replaced?? That's in excess of £350 for a compress + VAT I suspect and deffo + labour. I reckon I will won't I!!!

it can be - not sure if you can buy kits new or go second hand? what car is it on? alot of pumps are interchangeable. i usually sell mk4 golf pumps for £30

It's a 2000 W Reg 1.4 (75) Polo 6N2.

Presumably the same as the MK4 Golf as the engines are the same (if we're talking about 1.4s atleast) - but I'm not sure what you mean by "pump" when we're talking about a/c compressor clutches. Soz