I just did the head gasket on a 2009 Golf 2.0 TDi (CBAB) and at the end I had one nut left over (in my defence there was quite a long period between strip down and reassembly).

It appears to be M7 with a 13mm head on it. It looks like an earth strap type fastener, but I didn't need to remove one when doing the head and am at a loss as to where it belongs. Wondered if anyone familiar with these engines would recognize it.

Please see picture

IMG_20181015_155827.jpg

Thanks in advance

Adam