I just purchased a low mileage, 2001 Toyota Sienna with the supposedly "sludge producing" engine. At 27K all the service has been done by a Toyota dealer and the engine is sludge free...as far as we know. I do all my own maintenance, so it'll be getting Pennzoil or Chevron 5w-30 with a NAPA Silver filter from this point on. I don't see any major benefit of a synthetic with an OCI of 3-4K? (I could be wrong...and usually am) Is this reasonable combination of dino oil and filter? Any thoughts?