Posts Tagged: oil color

Why motor oil turns black

Here’s why motor oil turns black Soot from incomplete combustion turns motor oil black All internal combustion engines create soot as the fuel is burned. Some of that soot makes its way into the crankcase due to blow-by. Soot creation is highest during cold starts due to partial combustion caused by the cold metal “quenching” effect. But even after the engine is warmed up, combustion isn’t always 100% efficient because the air/fuel mixture is never 100% accurate. The computer tries to calculate the exact air/fuel mixture and it could easily … Read More