Dear Forum: I have a 2010 KIA Ceed 1.4 liter 90 HP engine. 145k km. 90k miles. It takes 3.5 liters 3.7 quarts of 10w40 oil. Currently uses about 0.9 liters per 1500km or a quart per 950 miles. KIA recommends an oil change every 15k km or 9k miles. I do it at 10k km or 6k miles. Since I am adding almost double (6.5 liters vs 3.5) between oil changes why not just change the oil filter? I probably will NOT use this "logic" but I still want to know why not. Also should I switch to 15W40 to reduce oil consumption? God Bless anyone who can answer these questions.
KIA recommends an oil change every 15k km or 9k miles. I do it at 10k km or 6k miles.
The general rule of thumb is 5000 miles, but 6000 is not too bad especially if you do a lot of highway driving.
Since I am adding almost double (6.5 liters vs 3.5) between oil changes why not just change the oil filter? ... I still want to know why not
It's very simple.
Q: What do you get when you add 1 quart of clean oil to 3 quarts of dirty oil?
A: 4 quarts of dirty oil.
You will greatly accelerate engine wear with that idea and Kias have pretty lousy engines to begin with, which is why it's using so much oil at 90,000 miles. (In contrast my own daily driver is 28 years old with well over 370,000 miles and it does not burn oil, just seeps a bit here and there. There is no need to add any oil between 5000 mile changes.)
should I switch to 15W40 to reduce oil consumption?
No. Not only will it probably not help, but using a heavy oil can mess up the variable valve timing mechanism. The heavy oil trick is OK for a really old car like a 1965 Chevy or a 1949 Hudson but not for anything modern.
