Engine / Transmission Under-tray Bolt Thread

LukeKirby

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Good afternoon,

2016 Audi A6 Avant (C7) 2.0 TDI SE Executive
Engine / Transmission Under-tray Bolts


Recently purchased the above vehicle, and am currently on a voyage of discovery, fixing all the silly little things, while simultaneously looking out for larger surprises along the way.

My transmission under-tray is currently only held on with zip-ties.
After some googling it would seem it is traditional to use the 1/4 lock Audi screws.
I am not a big fan of those, so I have installed the standard self-tapper and clip arrangement, which works well for 5-off locations.

In addition to the five locations mentioned above, there seems to be three additional securing points (where the transmission and engine cover overlap) where threaded inserts are used.

I have tried to identify the thread designation but have had no joy.
I am concerned the threads may be damaged (when the tray got ripped off), but am reluctant to run a tap down there unless I know the correct thread diameter and pitch (metric, imperial?)

Can anybody please help?

I apologies in advance if this has already been covered in another thread, but I could not find a definitive answer.

Kind regards,
Luke
 
I'd take a look here and try to find them... most of the undercarrage bolts aren't even a real thread they're a very sloppy thread based on M4 or M6 most are plastic.


Thank you so much, that is such a useful website...

I found the bolt, it was M6 x 18

Part #N91140701

Found these.

Thanks again for your help.
 

Stainless all the way!

I like the idea of the pan head (built in washer that mechanics can't lose), also a low-profile head.

I ended purchasing these,

 
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