Originally Posted By: mechtech2
After 250,000+ miles on dino, see if you need to alternate to a synthetic for cleanliness .
Seriously? I've gone 150K on conventional and have had no dirt/sludge/varnish issues whatsoever. It's all about the interval my friend.
Synthetic oil is made in a lab, not in heaven. Conventional oil was made in a lab too... with components taken from the earth... again, it's not blessed by the almighty.
If the motor is clean, run a full OCI interval... if it's not, run shorter intervals with a quality oil... it does clean up.
Just DRIVE THAT THING!