cvh sump gaskets are notoriously known for leaking if not fitted correctly!!! DO NOT use any sealing compound on the majority of the gasket! a little silcone sealer around the rounded area's at each end will do the job! if your doin it with the the engine in the car? then what will help is if you get some 6mm bolts,saw the heads off,then saw grooves in the top of them (so you can get them out after with a screwdriver) then screw them in every other bolt hole. when the sump is back up in its position, screw the proper bolts into the empty holes,then remove the bolts with the heads cut off and replace with the proper bolts! make sure you do the bolts up in a diagonal fashion and to the correct torque.