Originally Posted by evilfij
...the ones I would not recommend are 15w50 Mobil one (caused lifter rattle and seemed to eat power)...
Can't argue with that - just switched to Mobil 1 15W50 and can definitely hear that lifter rattle for a quite a few seconds on start up. I'm tempted to switch back to dino 20W50 per Chris Crane's logical explanation...
Previously used Castrol Syntec 5W50 with no lifter noise that I was aware of. Anybody else doubting the benefit of synths. in our engines?