TECH TIP

My oil's dirty...what's wrong?

You've probably encountered oil change customers who are concerned that the dirty oil you drain from their vehicles is a sign that something is wrong with their engines. This concern is based on the common misconception that a high-quality motor oil should come out of an engine looking clean at the time of an oil change. Nothing could be further from the truth. If the oil is doing its job cleaning the engine, then it should be dirty and black when it is drained. Motor oil will start getting darker shortly after it is put to use. In the case of diesel engines, the oil will darken within a few hours of operation. This discoloration is a sign that the motor oil is doing its job of keeping soot, dirt and other combustion contaminants in suspension to be carried to the filter or removed from the crankcase when the oil is changed.