I dont think the seals are the correct prob with your engine. I've would more look into worn cylinder and/or worn piston rings. This is how you check the "health" of these parts (as an indicator, not exact science..)

With a firm warm engine, you do an "pressed" accelration in the car, drive the engine "thru" the gears, and when you reach, let just say 80 km/h (apr. 50mph) you de-clutch and sort of let the engine "gasp" for just a few rpm, and then you give the engine a gaspedal-kick (still NOT in gear..) -if the smoke is blue-colored it shows that your engine burns oil, = worn engine, and will only get worse for every mile.. Theres is no "wonder-cure" only a replacement of pistonrings and of course a cylinder-"polish"..

Hope you understand! - sorry for my "not-so-firmly-technical-english"