Hey guys, I'm replacing the head gasket on a 2016 LR4 HSE with a SC 3.0 V6. I have the engine mostly broken down, with the crankshaft locked in place using the specialty tools. I'm trying to determine if the crankshaft bolt is lefthand(reverse) or righthand(standard) thread. From everything I've read, the way to tell is a stamp on the bolt (12.9 for lefthand/10.3 for righthand) however, the stamp is partially worn off and it could appear to be either. Is there another way to determine which thread pattern this bolt has?

As you can see, it appears 12.9 could be stamped on the top, but it also appears that 10.3 could have been stamped on the bottom.

 

I’ve yet to run into a right hand standard bolt, meaning all the motors I’ve worked on have a left hand thread, reverse.

just did a 2017 Discovery 5 engine, reverse thread. Hope this helps.

 

Don’t forget to straight edge the block, a fair amount of HG jobs fail because the block is more than .005” off.

 

It ended up being reverse thread.

Also, I just got a precision straight edge for checking the block and heads.
Thanks for all the help.