Not always. The oil pressure light doesn't monitor oil level, though it's still related. The engine oil pan actually holds more oil than the engine needs. This is so there's always a supply ready for the pump to pick up. The pressure sensor monitors this pressure produced by the pump. If the oil level dips low enough, the oil pump will suck air and the pressure level will drop. Then the pressure sensor will notify the computer. But exactly at what oil level will produce a significant pressure drop varies.
So at some point the pressure sensor would notice. But maybe 3 quarts wasn't enough.
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Wednesday, February 16th, 2011 AT 12:19 AM