A low oil pressure warning light or on-dash message is becoming a more frequent complaint from owners of many late model gasoline powered vehicles, especially those with engines fitted with solenoid controlled valve lifter systems. These types of engine first started appearing around 2005.
What causes a low oil pressure warning
In an attempt to eliminate the low oil pressure warning signal, some technicians have replaced the oil pressure sensor. Often times this procedure has not yielded positive results, and the warning signal remains activated.
Also, the oil and oil filter are changed in an attempt to solve the problem. Sometimes, multiple oil filters are changed out in the hope that a different brand of filter may deactivate the warning signal! When this doesn’t solve the problem, the assumption is that problems must exist within the oil pump itself, or even worse, serious engine related problems are to blame.
An overlooked element of some of these types of engines is a small filter screen that is positioned beneath the oil pressure sensor. It has been found to often be heavily sludged, consequently restricting the oil supply to the oil pressure sensor. This is what causes the warning signal to activate. The purpose of the filter screen is to control the amount of contaminants that are in the oil that flow through and activate the valve lifter hydraulic system, including actuator solenoids.
Fortunately, this filter screen can be removed, cleaned (or replaced with a new part) and refitted – though it is not a job for the novice DIY mechanic, and is time consuming. But… the underlying problem is not addressed. In a short period of time, sludge will again clog the filter screen.