Three problems related to engine burning oil have been reported for the 2008 Toyota Scion Xb.
My vehicle is consuming an excessive amount of oil. This issue started at roughly 58k. I have never been low on oil at any oil change. I was approximately 3qts low at 58k with no signs, at all of an oil leak. I took my car to Toyota where an oil consumption test was performed. I was then informed that my engine is having the oil consumption problem as listed in a TSB issued by Toyota on August 11, 2011. Because my car is no longer under the power train warranty, Toyota is refusing to cover the costly repairs.
Engine locked. My car was diagnosed with "oil starvation", which was due to scion's "oil consumption" problem. Because I did not have my oil changes done at the dealership, they found a loop hole to avoid paying for a new engine. There has been a TSB issued on this problem and scion refused to take responsibility.
After around 50k miles, I noticed that the engine oil was about a quart low when taking it in for an oil change. At the time I was told pretty much what the owners manual states about oil consumption. I've owned many vehicles in the past, old and new, and never had one that used this much oil. If any of them did use oil, it was a small enough amount that you can't tell from the dipstick. So, with their explanation I moved on. As time went on, it seemed more and more oil was being used by the engine. Now after the warranty would no longer cover such a thing, I was told that I could bring the vehicle in for an oil consumption test, which I did not do since any problem they discover would come out of my pocket. As time progresses, the vehicle is at the point where I have to check the oil every week and add oil. I learned that if I wait for the next oil change @ 3000 miles, there is no oil left in the engine. What's even more disturbing is that there is no indication on the instrument cluster that anything is wrong. I would suspect the oil light would come on at some point, but never have I seen this light, or any other light come on indicating an issue. To sum it up, there are no leaks, the engine will consume all of the oil within 3000 miles if not monitored, and there are no warning lights indicating a problem.