Originally Posted By: SatinSilver
Not sure I'd extend the interval any. I'd go 7k miles and do another UOA. What oil did you use for this oci? How long was the oil in use? Was any towing or a lot of short trips done? The Iron reading seems high even though it's under the universal average.
You may want to try some MaxLife 5w30 and compare the results.
Thanks, I have no plan to extend the OCI, I was mainly concerned with determining if the GM oil life system was something for me to trust with it going the 7,000 - 7,500 range regularly. That range works out to be 3 - 4 months and works perfectly with my desire to rotate tires and check the truck over in general. Truck is daily driver, no towing of any significance at this time. I am running M1 5w30 High Mileage Full Syn. This OCI was approx 3.5 months.