Question 15Motor Plants - QMED

The correct answer is D) the pressure drop across the filter. A dirty diesel engine oil filter element can best be detected by the pressure drop across the filter. As the filter becomes clogged with contaminants, the pressure drop across the filter will increase. This increased pressure drop indicates that the filter is becoming restricted and needs to be replaced. The other options are not as reliable for detecting a dirty oil filter. Visual inspection (A) may not always reveal the true condition of the filter. High lube oil sump temperature (B) and decrease in oil viscosity (C) can have other causes besides a dirty filter.