My truck has a little over 25K on the clock. I was changing the oil every 7.5K regardless with Amsoil 15W-40, Fleetguard Stratapore LF16035 and Amsoil bypass filters since it turned 10K and every 2.5K with dino oil till it reached 10K. I was going to continue with changing the oil and filter every 7.5K but I thought just maybe I can extend the interval with oil analysis. Well this is my first analysis with 7,634 on the oil/filter. Iron is the only metal above average and TBN is still 9.7 from 12 Amsoil publish. In your opinion, can I go another 5K and another analysis or just change the oil and filter then?

 

on my 03 I was going 14,000 between oil changes on Extreme Blue

 

One analysis is only a snapshot in time, yes the average data is nice but not worthy of your question. You would need to trend your oil analyses with at least three oil change interval analyses. If the average values are constant with published data attributes, double your interval if not (and Fe or Si are increasing) sell truck. Also if the trend is exhibiting an increase in Fe content, sell truck.

 

I have a similar filter set up and use the same oil and generally I am good with 15k changes. The oil itself is still very good at that point but I border on excess soot. And due to the twins and no airbox for the filter, I have a little higher levels of silicon.

 

How do you capture the oil sample? Is it drawn through the dipstick tube? or do you capture it mid drain? Is the oil at full operating temp when capturing the sample or is it cold? What kind of container are you capturing the sample too?