sealing O ring

[skippy41]

Is there meant to be an O ring on the cap of the expansion bottle????

[JakeBlade]

Which expansion bottle?

[skippy41]

Which expansion bottle?

There is only one, for the engine coolant

[Guest]

If all the Superb MkII vehicles have the same expansion tank there is no o ring, the cap has a definate click lock and no provision for a ring. There is though an o ring on the pressure relief unit in the centre of the cap, I did find on My second 170 ps MkII that removing the filler cap a week after a 400 mile run that there was a vacuum in the system, the centre unit was quite tight so I lubricated the o ring, the centre then moved easily and when removing the filler cap when cold after long runs no vacuum was still in the system, the first thing I did then with my next two 170ps MkII vehicles was to lubricate this o ring.