Low oil pressure in your 2010 Chevrolet Suburban at 200,000 miles is a serious symptom requiring immediate attention. Oil pressure keeps the engine alive, and low pressure indicates wear or failure in the oiling system that can cause rapid engine damage.
Understanding Oil Pressure
Oil pressure is created by the oil pump and maintained by tight clearances in bearings throughout the engine. As bearings wear, clearances increase, allowing more oil flow that reduces pressure. The oil pump can also wear, reducing its ability to maintain pressure.
Code P0520 Significance
P0520 indicates an oil pressure sensor circuit malfunction. While this could be just a sensor problem, it can also mean the sensor is correctly reporting low actual pressure. Never assume it's "just the sensor" without verification.
Causes of Low Oil Pressure
Worn main and rod bearings increase clearances. Oil pump wear reduces output. Oil pickup screen clogging restricts flow. Using incorrect oil viscosity. Low oil level. At 200,000 miles, bearing wear is the most common cause.
Verification Process
Install a mechanical oil pressure gauge to verify actual pressure. Compare readings to specifications at idle and 2,000 RPM. If pressure is actually low, the engine has internal wear. If pressure is normal, the sensor or wiring is at fault.