My 2000 Toyota has 282,000 km on it. The front valve cover has started to leak so I decided to pull the cover and have a look. The last 7 oil changes have been Pennzoil Platinum 5w30 at about 8000 km OCI. Prior to that I used brand name (Pennzoil conventional, Castrol GTX, Quaker State, etc) 5w30 conventional changed at 10,000 km on average. I have changed out the PCV valve 3 times. The Cam lobes still look very good!