Originally Posted By: stchman
It appears to be the consensus of most on this forum to be the following:
Conventional oil - 5K
Synthetic Blend - 6K
Full Synthetic - 7.5K
Premium Full Synthetic - 10K
I can't speak for others, but I don't strictly agree with those numbers, and I'd say that Ford doesn't either.
... One major thing that would affect those numbers, at least for me, is the car being used. For some cars, 5k on dino would be pushing it, but for other cars, 5k on dino is easy.
For me, and my daily driver - my 2010 Fusion - those numbers are way off. Ford specs a 7,500 mile OCI for this car under normal driving conditions, using their semi-synthetic. I have found that running a 'home-brew' blend of about 75% dino and 25% synthetic also works very well for the same 7,500 mile OCI - This using a regular MC FL400s filter.
.. so based on this, and assuming a premium filter, I'd adjust those numbers to:
Conventional (SuperTech, Valvoline conventional, Peak) ~ 5-6K
Premium Dino (Pennzoil Conventional, Quaker State Conventional)/ Synthetic Blend (MC, Valvoline MaxLife, 76Super) ~ 7-9K
Full Synthetic (Quaker State Ultimate Durability, Valvoline Synthetic) ~ 10-12K
Premium Full Synthetic (PP, Mobil 1 Extended Performance)~ 15K+
I'll qualify them by saying anyone considering the really long runs, like the 15K+, should get a used oil analysis done from time to time.