Q: Oil pump and oil sending housing unit

Hi there, thanks for writing in. The oil pressure gauge monitors the oil pressure in one of the main oil ways near to the pump and filter. There is a hole tapped into the engine block with a sensor (for electric gauges) or an oil pipe take-off (for mechanical gauges). Mechanical gauges work by literally forcing the needle around the dial under pressure from the engine. Electric gauges, on the other hand, work by using the sensor screwed into the engine block to produce a variable resistance that affects the amount of current passing through the circuit containing the gauge and sensor. When either of these applications fail (yours is likely an electrical gauge), this will cause an incorrect oil pressure reading in the dash which can be very fatal to an engine if not caught very quickly. The oil pump is what circulates the oil throughout the engine. This can fail for a variety of reasons. Fortunately, you have caught these before any major engine damage has happened. If you’d like help getting these units replaced, I would recommend having an expert from YourMechanic come to your home or office to perform the replacements.