As title the camshaft oil seal leaks when the engine (CVH) warms up up to normal temperature, coating the cam sprocket and spraying it everywhere

Ive fitted two new seals, one from a motor factors and one from Ford but its still doing the same, WHY!?!?

Am i fitting it wrong? would running on thinner oil do this? any ideas? talk about throwing a spanner in the works

Anyone?

Gray