NISSAN 25240-8996E Oil Pressure Switch

This genuine OEM NISSAN (OEM: 25240-8996E) oil pressure sensor (also known as an oil pressure switch or sender) is an essential component for the safe and optimal operation of the engine lubrication system. Its function is to continuously monitor the oil pressure within the engine block and immediately send an emergency alert to the driver and the engine control unit (ECU) in the event of a critical pressure drop.

Operating Principle and Importance

The oil pressure switch is an electromechanical or piezoresistive sensor screwed directly into the engine's oil gallery. When the engine starts, the pressure generated by the oil pump actuates the sensor's internal diaphragm, which opens or closes the electrical circuit. If the oil pressure drops below a specified safety threshold (typically 0.2–0.5 bar), the sensor closes the circuit, illuminating the red oil pressure warning light on the instrument cluster. A lack of adequate oil pressure can lead to catastrophic damage to internal engine components (crankshaft bearings, camshaft, pistons) within seconds.

Technical Specifications and Construction

• Manufacturer: NISSAN (Genuine OEM part)
• Part Number: 25240-8996E
• Part Type: Oil Pressure Switch / Sensor (SW OIL PRESSURE)
• Material Composition: Corrosion-resistant brass and high-strength, heat-resistant composite plastic housing for maximum durability.
• Connector Design: 1-pin electrical connector ensuring stable signal transmission even under high vibration.
• Sealing: Integrated tapered thread or sealing ring design for leak-free installation.

Typical Symptoms of Failure

Due to continuous temperature fluctuations, vibration, and exposure to chemicals, oil pressure sensors can wear out over time. The most common symptoms of failure include:

• False Warning: The oil pressure warning light illuminates or flickers on the dashboard unnecessarily, even though actual engine oil pressure is normal.
• Oil Leaks: Engine oil may seep through the sensor's internal diaphragm or the plastic electrical connector, leading to oil loss and connector corrosion.
• Warning Light Fails to Illuminate: When the ignition is turned on (with the engine off), the warning light fails to illuminate at all, indicating an open circuit within the sensor.

To protect the engine, a malfunctioning oil pressure switch should be replaced immediately with a reliable, genuine OEM component.