Maybe someone has felt with this before, on my 2007 4.2sc the exhaust manifold bolts keep coming loose. I can tighten them and have a day of silence then by the end of the next day the leak is back just as bad and the bolts are loose again. I have tried tightening when hot and when cold. any suggestions? Thanks

You could try Loctite or maybe some stage 8 fasteners.
http://www.stage8.com/imports.html

New one on me! Try new fixings???

If exhaust bolts nuts or studs have been used it's always best to replace them with new

Thanks everyone, I seen that looking at Jaguar parts exhaust manifold bolts. They come new with a thread lock sealant on them and no lock washers etc. Never seen that before, I'm old I guess 😩. Good news, know they're not seized. Guess will pick up some lock tite, thanks again for the help.

seems like loctite 2620 is the product to use.

Question regarding this:
How can you reach al the bolts of the exhaust header?
I can't hardly imagine reaching the bolts, removing the studs is not doable? MY2008 Buckingham Blue Supercharged - gone
MY2016 Santorini Black 4.4 SDV8 LWB AB

it is way way easier than it looks, especially if you have access to a hoist. 3/8 drive socket, u-joint, long extension and think it wall like a 13mm. you can get all but two easily from below, front drivers side one from above after popping off air filter box and finally the front passenger side one I couldn't get to because of alternator heat shield in way. It appears I must remove the alternator to get to this bolt so I would arrange to have the alternator rebuilt at the same time ( always like rebuilt over new).

Problem is with a universal joint on socket you can't really tell how much torque is going into turning bolt apposed to binding the u-joint. Wish they made one geared like a Tatra drive train.