Originally Posted By: 13Tacoma
I have always used Dino for 5k ocis, but I decided to give synthetic a go. I'm at about 8,750 miles on this current oci of pennzoil ultra in the is250. I've never done a uoa, and was wondering if I should dump it at 9k and call it good or get a uoa to see how the oil held up and if it's safe?
A UOA can tell all kind of valuable information. But it costs $25 which is about what an oil change costs. A UOA is good if you are trying to push the OCI, concerned about an engine issue, or you have a large sump (several gallons) where doing UOAs to determine when to change the oil makes $$ sense.