Originally Posted By: JOD
My point was that 1) he probably didn't do any damage and 2) the thicker oil didn't cause the leak...
Agreed, on both counts.
Originally Posted By: JOD
..if the car were consuming a thinner weight past the rings versus leaking it, it's entirely possible that the extra oil pressure from the thicker oil contributed the problem.
The piston rings are lubricated from splash lubrication coming off the crank, not pressure. The thicker oil may have contributed by not being present on a cold startup, creating more cylinder and piston/ring wear, but there is no pressurized oil on the rings.
Originally Posted By: JOD
Then again, there's no way of knowing that the thicker weight oil and increased oil pressure didn't at least in part contribute to the main seal leak, particularly if this car isn't prone to that (I don't know either way).
History has shown this engine is definitely prone to main (front and rear) seal leaks as the miles rackup, however pressure wouldnt cause that. There is no pressurized oil on either side of the seal. Sunshine on the outside, and the open air of the crankcase behind it. The main seals only see splash lubrication.