Originally Posted by tom4416

Have been using Mobil 1 5/30 since the second oil change on my 2003 and change oil/filter every 5K and send a sample to Blackstone about every 3rd change. The story is the same every time - a strong recommendation to extend the OCI to at least 7500 miles. I've talked to them on the phone twice and the engineer was emphatic about going at least 7500 miles and more likely 10,000. I used to drive in heavy traffic in the Washington, DC area - same results. Now drive in low/no traffic Tucson and the results are the same. Only Toyota filters and I still stick to the 5K OCI. BTW, Blackstone has never been a proponent of the time versus miles argument, within reason. It now takes me a year to do 5K miles and they are still comfortable recommending 7500 even though that would run up against 18 months.