What size spark plug spanner do you need for a vauxhall astra 1.6?

Unless someone has fitted the wrong plugs, for both 8 and 16 valve engines you will need a 10mm plug spanner, which is 5/8" (or 16mm) across the flats. Both engines have the plugs way down in the head, so a good quality plug socket with a rubber insert, and with a locking mechanism to the socket extension bar is recommended.

(If the wrong plugs have been fitted, the socket size is 13/16 (21mm) AtF)