Some think that the factory puts in a special oil meant to break in the engine. Others think this is false. I recommend changing the oil after 4 months or 5,000 miles. Most importantly, do it yourself using a mazda filter. Save all filter and oil receipts to prove that the oil was changed if you ever have engine problems.
I called Mazda. They said a break in oil is not used on the 10 Mazda 3. However, I reccomend an oil change at 1k or 1,500 miles. Probably not needed, but inexpensive way to get rid of any break in junk. Free first oil change at dealer made it easier. Picked up the Mazda 2.5 liter oil filters while there for $7.00 each.
I've never owned a turbo, but I'd change the oil more frequently in a turbo.
I changed mine at 400 miles also and Im glad I did. The original oil was dark black with the consistancy of water. I switched to mobil1 5-20 and a pure one filter. I have noticed that the engine doesnt idle rough anymore at stop lights. It's been 500 miles since I changed it and the oil is still a nice amber color. Next change is at 3500 and then 5000 therafter.
