Hi all
I have a 850 GLT with 140,000 miles. It has just been serviced, passed emission tests and has no oil leaks. Yet, it is now doing 350 miles to the litre of Mobil 1 (0W40 - synthetic). Is this high consumption due to using Mobil 1? Can any body suggest some diagnostics that an amatur like me can perform.
Stuart Dentt