Mitsubishi says it is safe to change your oil at 7500 for easy driving conditions and 3750 for severe here in the US. Thats about 12000 normal and 6000km severe.
New engines normally have a "break in period" around the first 500 to 1000 miles for cars, the engine has more wearing going on with all of the internal components being very tight.
The build date on my Mirage is September 2013 so that oil has been in there for over 15 months, which the manual says 6 months for standard driving and 3 months for severe. Lots of condensation can build up in the oil over time which is why they say change it 3/6 months.
The last thing is I have no idea what brand/quality oil they used when building my Mirage, I wanted to take a sample for testing but the Walmart trip threw things off course.
So I changed it for my piece of mind, its my first new car and I might be a little over kill lol.
I read a lot of reviews on oils from bobistheoilguy.com and they say that redline is one of the best for modern engines but for price. Eneos is the number one Japanese oil out there, it is ranked very high and the price is almost reasonable at 7.75/qt. Amsoil and redline are both priced around 14.00 per quart which is almost double, Mobile 1 eco is 5,20. Toyota uses a type of Eneos oil for there engines, its a slightly different blend they say but its almost the same price as my local Eneos supplier. If I was doing 7500 mile oil changes I could justify the redline but I am driving under the severe conditions in my owners manual and I'll be doing 3750 oil changes to keep my warranty, at 100K I'll start extending the distance when the warranty is over.
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View my fuel log 2014 Mirage ES 1.2 manual: 44.8 mpg (US) ... 19.1 km/L ... 5.2 L/100 km ... 53.9 mpg (Imp)