What is that hole in my engine?

[DHDamo]

Hi all, wondering why I have an unsealed opening on my engine, or actually on the flywheel housing. When viewed from the engine bay, the spot I'm talking about is to the rear of the exhaust headers about halfway up the block. The hole is supposed to be there but isn't threaded - should there be a bung or some kinda plug there?

Cheers.

[105gta]

I think that this hole is there for the injected cars(US) probably have a timing mark on the flywheel for the mechanical pump timing. They all have it. No big deal if it's not plugged, they never were.

[martym00se72]

I always thought it was for a flywheel lock to lock the engine when working on it - but that is just a guess with nothing to back it up...