I live in WA state and have changed the oil in mine 4 or 5 times, (in 5000 miles), also installed new lash adjusters, all trying to quiet the clicking sound down. Now I am running 20-50 and it shows good pressure and has quieted it down some! Just recently installed the newer exhuast manifold and turbo, next step is to take off the turbo and have it proffesionally rebuilt, I believe the oil ring is leaking! After installing it, I ran it for awhile and lifted the hood, looked like someone took 4 or 5 quarts of oil and threw it at the fan! LOL