The engine oil being a little low does not mean to say it is burning it. We have found that the 4E-FE engine is generally fairly heavy on oil when giving it some. I check and top up mine every two weeks, and under some cases every few days. Also, while we are on topic, I have just serviced mine using 15w 40 oil. Will I be okay using that? The shop I bought the oil recommended this for my car and the way I drive it, but I need more views on it!