My son has a 2012 Forester with the 4 banger. He has about 93k on the motor, but the bottom end was just replaced due to the oil consumption issue. My father-in-law has a similar Forester which has also had the same "fix" but reports the oil consumption continues. I realize this isn't exactly news, so my question is what viscosity oil might be worth switching to to decrease the oil consumption? TIA