It won't just be the gasket. The manifold will need a skim. Most of the ones I've encountered are about 1mm out over the length.
A number of methods for removal.
1. Take the manifold, turbo and CAT off in 1 piece. Saves undoing the 4 turbo - manifold nuts in situ., but undoing the oil feed banjo behind the turbo (and more to the point refitting, keeping copper washers either side of the banjo) is a pain.
OR
1. Undo the 4 manifold to turbo nuts (keep these separate, they are special and cost about £5 each). May require removal of turbo water pipes to access rear right with a spanner if you can't get from underneath with a socket & extension.
2. Undo the nuts holding manifold to head, hoping that the studs come out with them.
3. Remove the remaining studs. (Good luck
) hopefully they will have the bit on the end to allow a tool to unwind them.
4. If 3 is successful, remove the manifold upwards without disturbing turbo or cat.
OR
4. Remove the bolts holding the turbo bracket and 2 cat brackets to the block. Remove the bolt holding the oil feed return pipe to the block.
5. The flex you now have in the turbo should allow you to lever the manifold away from the head until it comes off the studs and then lift upwards. Don't pull further than needed as you are flexing the turbo oil feed pipe.
If any head threads are knackered, you need a helicoil kit for M10x1.25.
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