When to change the oil on a 2003 trailblazer?

Answer 1

This is my opinion based on my experience and knowledge. Oil change intervals are determined by how and where you drive. Assuming you drive in normal conditions and not very dusty conditions, change the filter with every oil change, and replace the air filter every 30,000 miles. This is what I would do. If you use conventional oil and drive mostly city stop and go driving, change it every 4,000 miles. Mostly highway, change it every 7,000 miles. A mixture of city/highway every 5,000 miles. if you use synthetic oil then city 6,000 miles, highway 10,000 miles, a mixture 8,000 miles. Remember the air filter is critical to keeping the engine clean. Change the air filter every 30,000 miles and more often if you ever drive in a dusty area. How you drive is also important. If you drive the car hard with full acceleration starts, the change it more often. Also buy a quality oil/air filter. If you purchase a Purolator, Wix, or AC/Delco filter you can't go wrong. All excellent filters. On your GM vehicle, if it were mine I would install a AC/Delco filter.