I never really allow my engine to idle, other than a minute or two at 1 traffic light before I hit the highway, and my driving habits have not changed since I last changed oil 2,520 km (1,575 miles) ago. Driving is 80% highway and 20% city at worst, and the vehicle barely ever sees city driving. But when I pull my dipstick, there's a faint to partially strong gasoline odour in the oil. This wasn't something I've experienced before, and I'm wondering if the fact that I switched to a thicker oil (+20 weight) have anything to do with it. This is also the first time this engine sees Group IV oil after a few ARX treatments, and I used a thinner oil before. Reason I switched to a thicker oil is to temporarily reduce burn off until I get my valves, valve guides and seals replaced. So far, it hasn't burned enough to actually make a difference on the dipstick. With same weight Group II oil in the past, I would have to add a full quart by 2,500 km. I suppose synthetic not thinning down as fast in intense heat has its benefits as I thought. But the gas smell has me a bit worried. Any idea what could possibly be the cause? Engine in question is a Mitsubishi 3.0 V6 12-valve. Thanks!