TDC sensor mentioned in Haynes

[marcus]

Haynes mentions (chapter 4, section 13) "...a TDC sensor unit is located on the gearbox casing ... and may be used with a special VW tester... However, this tester will not normally be available to the home mechanic".

Where is this sensor? And just how 'special' would this tester need to be?

[Nate]

Do they mean take a bung out so you can look at marks on the flywheel?

[marcus]

I hope not, 'cos my flywheel has evidently been removed and replaced incorrectly at some point in the past, so when the engine actually is at TDC, the mark is nowhere to be seen, it's several tens of degrees out, can't remember exactly, think there's six bolts on the flywheel, so imagine it's either 60 or 120 degrees out.

[bengould]

I might be wrong but im quite sure you can only put the flywheel on one way because of how the bolt holes are arranged.

Ben

[mr.brown]

I think it's the six pressure plate bolts that are in a non-symmetric pattern. There are nine flywheel bolts in three groups of three. There is a locating dowel on the flywheel to prevent it being fitted incorrectly. No good if someone's removed the dowel though.

Never heard of any kind of sensor in there though.

[marcus]

Must be the dowel then, it's definitely not correctly aligned with the crankshaft.