Wellllll, now that the thread is derailing (a little
) my personal experience on 2 different vehicles with different circumstances is this:
1. 1999 Dodge Ram, 5.9l V8, bought new. Changed factory oil at 2000 km with dino, changed to synthetic at 5000 km and have run 0w30 synthetic ever since. Currently at ~273K km and neither burns/uses/leaks zero oil, I changed oil every 10K as I was doing almost all highway miles.
2. 1986 Volvo 740, b230f, bought new. Changed oil as per factory spec with dino till ~ 180k km and switched to 10w30 synthetic. Car ran fine with zero oil use, leaks etc. till ~ 470K km when it developed a RMS leak (damn synthetic
). Switched back to dino and followed the Auto-Rx procedure for oil leaks, leak stopped so I switched back to synthetic because I thought it was so much better than dino and leak started again.
Went back to dino and followed the ARX procedure AGAIN and sealed the leak. The car was fine to 484K km when it was retired last month with Fred Flintstone floorboards.
A testament to redblocks that motor never had oil added to it except when it was leaking.