We will probably trade off the Sienna in a couple of years so I will probably stick with the 3000 mile changes I have been doing on it. The truck however I will probably keep until it falls apart so I might consider going to mobil one in it. So you think that the PZ will hold up ok with 3000 mile changes in this harsh hard enviroment? Thats good to know. What weight of oil should I run in these vehicles? I have been using 10-30 as a rule.