My dilution issue is such that I can't really go more than 50% of my oil life indicator before the oil is at least 1/2 centimeter above the full line after being filled at oil change to below the full line. So I am thinking of doing more frequent oil changes (5 to 6k kilometers) but with a good quality conventional 5w20. Seems wasteful to change so often with a synthetic. We don't get cold winters and I am not hard on my vehicle. Any suggestions for a 5w20?