I have used Mobil 1 high mileage 10w-40 and it has more wear protection built into the oil. Its not a leak stop. As the other guy said above this. I am too will be switch over to Shell Rotella 15w-40 on the next oil change. My car seems to have a higher oil pressure with the 15w in hotter whether. I have a digital oil pressure gauge and keep my eyes glued to it. I like to see my oil pressure at 8-12psi at hot idle. The 10w Mobil 1 is to thin it seems here in Indiana on 95 degree days.

The White Shepard is supposed to expand and recondition rubber seals. If you get a bottle its $19.99. You must drive the car for at least 30min when pouring in the White Shepard.
Lucus Oil Stop leak is THICK like molasses. It seems to slow leaks down too. $14.99 a quart. I think you add 1/2 to 3/4 of a bottle to 6 quarts of oil. Those do work but you need to add them at each oil change which gets pricy.

After replacing the oil pan gasket and crank seal. I dont need any of the additives. I have a very slow leak with one drop always on the front of the oil pan. It probably the front cover seal. I'd rather leave the rock unturned till it gets worse.