Surprising sump plug


A previous owner of my 2002 AMF tdi has seemingly fitted a non-metric magnetic sump plug. A 9/16" socket fits the head perfectly. The body of the plug is about the same size as that of replacements that I have ordered and were supplied as being correct for an AMF, but the thread is different and they won't screw in. I deduce that a new non-metric thread has been cut into the sump, but this seems an awful lot of trouble for somebody to have gone to for so little benefit. The arrangement works perfectly well for the moment but I wonder whether others have come across the phenomenon?

This is a wonderful forum.


I think the standard sump plug thread is M14 x 1.5. Can you measure the thread on the new sump plug and compare.

It would not surprise me if an aftermarket drain plug was machined from 'imperial' hex bar - and there is always a slim chance they supplied the wrong part

Cheers Spike

Stan H

Try screwing your new plug into a known metric nut first if you have any about.
As Spike said it might be a wrong part.