Speedo is spot on, it's a 36mm socket that you require,which you may not have in your standard tool box, also from bitter experience can I recomend a long bar to attach to the socket ( and possibly a jack under the socket). Although my car had full VW service history and I changed my oil 7K miles after the last entry, I found it impossible to remove the oil filter housing, Having drained the oil and struggled for 2 hours to try to remove the case (persisted for so long so as not to waste my new oil) I eventually gave up put my new oil in, and got my local garage to do it, they needed a 5 foot