Spot,
I think 99% of all oil additives are some type of VI improver and being so deal mostly with friction issues. Your problem is a result of normal engine wear after years of use...something is worn out and the sealing function of the motor oil cannot overcome it.
I have no real life experience with trying to revive a worn engine through the use of an oil additive because I don't feel it can be done. Having said that, It certainly wouldn't hurt, from a experimental standpoint, to buy a can of snake oil and see just what it's capable of.
Stuart
