Subaru Coupes/Sedans/Wagons 1985-1996 Repair Guide

Oil Pressure Sensor

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OPERATION



See Figure 1

Click image to see an enlarged view

Fig. Fig. 1: Cutaway view of oil pressure switch

The oil pressure switch is attached to the crankcase (1.2L engine), oil pump case (1.6L, 1.8L and 2.7L engines) or cylinder block (2.2L, 2.5L and 3.3L engines). It monitors oil pressure and activates the oil pressure indicator light in the combination meter.

The sensor is made up of a diaphragm which is operated by oil pressure. A set of contacts open and close in relation to the diaphragm movement. The entire sensor is encased in phenol resin which is not effected by temperature or oil. The sensor is not serviceable, and must be replaced if found to be defective.

TESTING



  1. Remove the oil pressure switch from the engine.
  2.  
  3. Install a T-fitting into the oil pressure switch hole and connect the oil pressure switch to one end, and a suitable oil pressure gauge to the other.
  4.  
  5. Start the vehicle and allow it to reach normal operating temperature. Upon starting the vehicle, the oil pressure light should illuminate. If it does not, check the wiring to the indicator lamp for power.
  6.  
  7. At an oil pressure of 2.1 psi (15 kPa), the oil pressure indicator light should go out. If the light does not go out, replace the oil pressure switch.
  8.  

REMOVAL & INSTALLATION



  1. Disconnect the negative battery cable.
  2.  
  3. Access the oil pressure switch on the crankcase (1.2L engine), oil pump case (1.6L, 1.8L and 2.7L engines) or cylinder head (2.2L, 2.5L and 3.3L engines). Unfasten the wire harness from the switch.
  4.  
  5. Place a suitable drain pan underneath the oil pressure switch to capture any oil which may spill out during the removal and installation of the switch.
  6.  
  7. Use an appropriate wrench or socket to loosen and remove the oil pressure switch. If reinstalling original oil pressure switch, remove and discard washer on switch.
  8.  

To install:
  1. Position the oil pressure switch and new washer into hole on crankcase, oil pump case or cylinder head, depending on models, and hand-tighten.
  2.  
  3. Use an appropriate socket and tighten the oil pressure switch to 12-17 ft. lbs. (17-23 Nm).
  4.  
  5. Fasten the wire harness to the oil pressure switch.
  6.  
  7. Connect the negative battery cable.
  8.  
  9. Check the oil level and add oil if needed.
  10.  

 
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