Thank you,
Epoxy, locktite... prevent bolts or nuts from vibrating loose. Good thing to use it there.
The bolts are stretchable, so you have to tighten the bolt with a certain pre-tension. If you do it too loose, the gasket will leak with the known problems.
If you tighten it too much, the bolt may break!
I do it the old school way, tightening to a safe tightening torque. And then after 2500 km, check everything again. That is why it is important which bearing surface the bolt has, with a very low frictional resistance.
It's trial and error, but I'm used to that as an aircraft mechanic who has even worked and flown on the lockheed Neptune.
It's a Nissan Patrol RD28T, 6 cyl. diesel.1990.