Opel Forums - View Single Post - Fuel economy 'how-to' thread

bullmoose · 07-07-2007

Anyone ever test to see what happened to their gas mileage with different oil viscosities? I was running 5W-30 in my GT for a while, and when I replaced it with 20W-50, there was an immediate and noticeable drag on the engine. I had to adjust the idle on the old solex to compensate. I'm curious if anyone else ever noticed this and decided to see what happened to their gas mileage? Since the service manual says 10W30 is the recommended oil, what's the harm in low viscosity vs. higher. Either way, my ol' girl leaks like a sieve. I'd do it myself, but at this time, the ol' girl has too many other issues to work through before it becomes a reliable test bed.

07-07-2007	#36 (permalink)
bullmoose Hire me Now! Join Date: Oct 2003 Location: Kuna, Idaho Posts: 61 Classified Rating: 0% (0)	Oil Viscosity vs. Gas Mileage Anyone ever test to see what happened to their gas mileage with different oil viscosities? I was running 5W-30 in my GT for a while, and when I replaced it with 20W-50, there was an immediate and noticeable drag on the engine. I had to adjust the idle on the old solex to compensate. I'm curious if anyone else ever noticed this and decided to see what happened to their gas mileage? Since the service manual says 10W30 is the recommended oil, what's the harm in low viscosity vs. higher. Either way, my ol' girl leaks like a sieve. I'd do it myself, but at this time, the ol' girl has too many other issues to work through before it becomes a reliable test bed.