2009 Tacoma SR5 with 60k miles. Short tripped by my father, Job is 3 miles away, with occasional weekend 20-mile roundtrip. 5k OCI over the course of 1 year. Thoughts? Previous fill was Castrol 0w40 (???source of higher viscosity seen???) And butt dyno, along with perfect hearing, definitely likes the 0w20 in that truck. Can't say the same for my other vehicles...