I have a 2006 Chevrolet with the 6.6 Duramax diesel engine. I have been using DELO 400 15W-40 in it since I bought it, changing annually or more frequently if noted by by the OLM. I have not been putting many miles on the truck lately and it is coming up on a year since I did. The OLM still shows 80%. I have read where oil manufacturers recommend changing at 12 months. What would you guys do? Change when the year is up? Change when the OLM gets closer to 0% (that could be a few years based on usage)?
I have fresh oil and filter ready to go.
I have fresh oil and filter ready to go.