the manifold joint gaskets are sometimes called plastic gasket or something like that, I believe a strong oil and fuel resistant sealer like engine MB sealant, Gm engine sealant or toyota FIPG can seal it up if its just a metal to metal joint.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)