GMC SIERRA 1994 Manual page 138

Oil Pressure Gage
Standard Cluster -Gas Standard Cluster -Diesel
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I
Tachometer Cluster -Gas Tachometer Cluster -Diesel
The
oil pressure gage shows the engine oil pressure in psi (pounds per
square inch) when the engine is running. Canadian vehicles indicate
pressure in kPa (kilopascals). Oil pressure may vary with engine speed,
outside temperature and oil viscosity, but readings above the low pressure
zone indicate the normal operating range.
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