Originally Posted by
Mistah JT
Simple. My dad works on cylinder heads. The ones that come in with the most burnt thick black oil is valvoline.
If he is working on a cylinder head, it needs service, which could explain why the motor oil is discolored.
In any case, I'm glad you found a oil that you are happy with. I don't know what formulations are used there. Best wishes.
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View my fuel log 2015 Mirage ES 1.2 manual: 49.6 mpg (US) ... 21.1 km/L ... 4.7 L/100 km ... 59.5 mpg (Imp)