I don't think you'll be disappointed by Loctite 515 or 518. I worked at a tractor dealership. When separating the engine from transmission or the trans from the rear axle, 518 was required by the factory service manual. Anything less would allow flex which would break the seal and then oil on the floor. It's strong stuff yet it is not difficult to disassemble or clean off the surface. I use it on my bikes. You can use it alone or with a gasket.
Al