It's been in the company van, in my sig, since its' first OCI at 5,000 miles, changed every 5K, ML 5W20 (Ford requires a syn blend, VIOC no longer has Durablend), now over 106K, hasn't needed any added between changes yet.
Originally Posted By: oilchangeguy
Didn't know if long term use had any adverse affect on seals or gaskets.
Compared to what other oil? Seals and gaskets will eventually get hard and leak.
My first choice in an oil would be one that maintains the seals the best; I'm not so worried about shear and VI and all that jazz. My cars have been sent to their destiny due to oil leaks and not any type of oil related wear.