I own a 2010 KIA Ceed 1.4 liter 90HP engine with 5 speed manual transmission. I heard that to improve fuel economy some oil is allowed to combust. I have 165K km. or 103K miles. A few weeks ago I would add 800ml. per 1,500 km driven and my fuel economy was 6.8 liters per 100km. Recently I noticed the fuel economy was worse at 8.4 liters per 100km. The "good news" was very little oil consumption. Doing the math I rather top off the oil at 500km. or 300 miles and get better fuel economy. Yes, oil is 4X more expensive than gas but I rather add €6.50 per liter oil than pay €25 or more at the fuel pump. I think there is less friction when a small amount of oil is consumed. Thank you for any advice.
I heard that to improve fuel economy some oil is allowed to combust.
Where did you hear that? Too much oil burning can foul catalytic converters and O2 sensors. Modern engines can be more prone to oil burning due to low-tension piston rings which are used for a little better gas mileage, but the oil burning is an unintended side effect. The only engines where oil burning is completely normal would be 2-stroke engines and wankel rotary engines.
In normal auto engines a small amount can be tolerated. Dealers will usually tell you that up to a quart every 1000 miles is "normal" for warranty purposes. That's really too much. My daily driver is a 1997 model that has about 380,000 miles on it. It uses about 1/2 quart of oil between 5000 mile changes, and some of that is seepage. I would consider that amount of oil burning to be acceptable.
My daily driver is a 1997 model that has about 380,000 miles on it. It uses about 1/2 quart of oil between 5000 mile changes, and some of that is seepage.
That is amazing! What is your daily driver? I'll bet you're mighty proud of that baby.
1997 Saab 9000 turbo. I purchased the car in 2011 for $1500 with about 200K miles on it, thinking if I was lucky it might last a year or two.