 I purchased my '05 Mazda 6 in 2007 with 20k miles. The car ran great, had lots of pep and was very reliable. After 120k miles I started noticing the oil level going down with no noticeable oil leak. It eventually would not start and when I brought it to the dealer they found that the valve seals were leaking and the PVC valve was blowing oil into the cylinders as well as the throttle body. After having the those 3 things replaced and spending $1500, it is running fine. Perhaps this is considered routine maintenance or the dealer ripped me off so beware.