Originally Posted By: Triton_330
Originally Posted By: gallydif
I wouldn't do high mileage oil unless your engine burns or eats the oil.
HM Oil just has a slightly larger amount of seal swellers...
ERGO
for an older engine with larger/bigger clearances/tolerances than a newer engine (despite a rebuild)...
HM oil is preferred.
Period.
~ Triton
If the seals are fine, there are no need for seal swellers. HM is only needed in this application if the engine is burning, losing, or needing to top off oil. As the saying goes: "if it ain't broken, don't fix it." An oil with slightly higher levels of zinc would be preferred here to protect the engine such as Amsoil 10w-40 synthetic high zinc formula.