Dear Car Talk:
I have a 2009 Subaru Outback with 143,000 miles.
My check-engine light came on while driving. I have a device in the car that told me the engine triggered "Code P0028." I drove home and Googled the code: "Blah blah oil level, blah blah solenoid ..."
I barely know how to do self-service gas, but I do know how to check the oil. There was not a drop on the dipstick. Shocked (because I am faithful about oil changes and other maintenance), I was also puzzled because I was only 8 miles over the suggested mileage for getting an oil change.
The mechanic said I was not leaking oil so I must be burning it. But I've never seen any smoke or noticed a burning smell. The car has always functioned perfectly.
My mechanic said to check the oil frequently and carry a quart of oil in my car for those times when my oil is low.
I've driven 860 miles since then and my dipstick registers "full." Could the mechanic have been wrong about it burning oil? -- Mary
I don't think he was wrong, Mary. I think you probably are burning some oil.
If the oil had leaked out (and you would have to lose at least two quarts for the dipstick to register no oil), it would have made a mess somewhere on the engine, and your mechanic would have noticed it.
Imagine if you spilled two quarts of cooking oil somewhere in your kitchen. You'd find it. Even though your dipstick still reads full after 860 miles, that doesn't mean you're not burning oil.
The oil change interval for this car is about 7,500 miles. If you lost two quarts in 7,500, that's only a quart every 3,750 miles. So, it doesn't surprise me that you haven't seen any drop in oil in only 860 miles.
Plus, oil burning accelerates as you lose oil. If you start with four quarts, and let's say you burn a quart over 5,000 miles, now you have three quarts of oil trying to do the job of four quarts. It's working harder and running hotter. That means it may burn the next quart in 2,500 miles.
Your mechanic is right that you should check your oil regularly and top it up when necessary between changes. It would also make sense to decrease your oil change interval to every 3,750 miles from now on. Keeping newer, cleaner oil in there may help reduce the burn rate too.
But the bottom line is you have now entered the stage of car ownership we call "Heapdom." You are officially driving an old car, Mary. And at 10 years and 150,000 miles, it's right on schedule.
With a little luck, you'll be able to nurse this Subaru for tens of thousands of more miles. It will require some vigilance. And some more oil.