Mobil 1 0W40, Motul 8100 0W40, Redline 5W40?
Scenaro: 1991 Rover 3.9 V8, 78k miles, poor oil history (very light sludge), owned since 70k miles, driven on the Gulf of Mexico (hot). Current oil: Mobil 1 0W40 - OCI 5k miles (K&N 3001 filter) - I always liked the idea of instant flow on a...