Engine Oil Pressure Gauge Changes Based on Engine Needs

Engine lubrication on all 2019-2020 Silverado 1500 and Sierra 1500 trucks is supplied by a variable displacement oil pump. An oil control solenoid valve, controlled by the Engine Control Module (ECM), is mounted to the oil pump and varies engine oil pressure according to engine needs. As a result, the oil pressure may change quickly as the engine speed or load varies. Oil pressure may also vary with outside temperature and oil viscosity.

All of these factors play a role in the oil pressure displayed on the engine oil pressure gauge on the instrument cluster. (Fig. 16) In certain driving conditions, the oil pressure reading may drop or change quickly, which is part of normal engine operation. Some customers may question engine operation if the gauge shows more fluctuation and lower standard operating pressure than on previous models.

 

Fig. 16

 

Any engine conditions that are outside of the normal operating range and require service will be indicated by a message on the Driver Information Center (DIC). A DTC may set and the oil pressure warning light may or may not illuminate, depending on the engine condition. If a DIC message is not displayed, the engine and the oil pressure gauge are operating as designed and no repairs should be attempted.

The engine oil level, recommended viscosity, and condition are critical to the correct operation of the system. Remind customers to check the engine oil level regularly and follow all scheduled maintenance.

 

Variable Oil Pressure

The engine oil pressure control solenoid valve is used to control engine oil pressure inside the mechanical engine oil pump. (Fig. 17, shown on V8 engine RPOs L82, L84, L87) The control module controls the commanded state of the solenoid valve based on the following inputs:

  • Engine speed
  • Calculated engine oil temperature
  • Engine oil pressure
  • Engine run time

 

When the solenoid valve is commanded Off, oil pressure is higher. When the solenoid valve is commanded On, oil pressure is lower.

 

Fig. 17

 

TIP: On the 2.7L engine (RPO L3B), oil pressure may be as low as 26-28 psi (179-193 kPa) under normal operating conditions at road speed. The oil pressure at this level is normal and is not associated with any engine durability issues. If the oil pressure is not correct for current conditions, as commanded from the ECM to the variable oil pump, a DIC message will be displayed.

 

– Thanks to David MacGillis

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One Comment

  1. Mike Raffaelli says:

    Clarify, All trucks or just the gasoline versions???

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