Following advice from garage, I fitted a new coolant expansion bottle to my Octy mark 2 today. Still get coolant warning light. Any advice on next step please.

Have u had a scan of the instrument cluster?

you have to measure wiring 1st is ground ans 2nd is signal to cluster, check it

I had this issue and it was the oil cooler. Coolant was getting mildly contaminated with oil which fouled the water level sensor in the bottle.

I had this issue and it was the oil cooler. Coolant was getting mildly contaminated with oil which fouled the water level sensor in the bottle.

Hey thanks for the swift reply guys. I think the grounding issue could be a factor. I removed a taximeter which had been wired in and problems ensued after this, including my fuel gauge only working intermittently.

Have a mate who is a vag technician and will be seeing him next week so will mention your points to him. Thanks again for the replies.

ground is brown/white wire