Low oil pressure means the oil pump is not pushing enough oil through the engine to protect the bearings and valvetrain. The most common causes are a low oil level, worn engine bearings, a failing oil pump, a clogged oil pickup, the wrong oil viscosity or a faulty pressure sensor. If the oil pressure light comes on while driving, pull over and shut the engine off as soon as it is safe, because running without oil pressure can destroy an engine in minutes.
What to do when the oil pressure light comes on
- Pull over safely and switch off the engine.
- Wait a few minutes and check the oil level on the dipstick.
- If it is low, top it up with the correct oil and look for leaks. If the light goes out and stays out, have the cause found.
- If the level is fine and the light stays on, or you hear knocking or ticking, do not drive it; have the pressure checked with a mechanical gauge.
Common causes of low oil pressure
- Low oil level: from leaks or oil burning; see blue exhaust smoke.
- Worn bearings: wear in the crankshaft and rod bearings lets oil escape and pressure drop, especially when hot at idle. It often comes with knocking; see engine knocking.
- Failing oil pump or a worn pressure relief valve.
- Clogged pickup screen from sludge after missed oil changes.
- Wrong viscosity: oil thinner than specified, or oil diluted by fuel.
- Faulty sensor or sender: a bad sensor can light the warning with normal pressure, which a mechanical gauge test reveals.
What is normal oil pressure?
It varies by engine, temperature and engine speed, so use the specification for your engine. A common rule of thumb is roughly 10 psi for every 1,000 rpm, with lower readings at hot idle than at cruise. A sudden drop from what is normal for your engine matters more than any single number.
Preventing low oil pressure
Change the oil and filter on schedule with the viscosity your manual specifies, check the level regularly, and fix leaks early. Sludge from missed oil changes is a common reason pickups clog and pressure falls.
Can low oil pressure be fixed?
Low level, the wrong oil, a clogged pickup or a bad sensor are straightforward repairs. Worn bearings or a damaged crankshaft mean internal engine work, and if the engine has run without oil pressure, a replacement short block or long block is often the better choice; see short block vs long block and our engines by engine code.
More guides: oil pressure sensor: bad sensor or low pressure? · oil pressure light on · seized engine · synthetic vs conventional oil · Subaru oil pickup tube · bad oil pump symptoms.
Trouble codes: P0521 Oil Pressure Sensor Range/Performance · P0520 Oil Pressure Sensor Circuit · P0011 Intake Cam Timing Over-Advanced · P0016 Crank/Cam Correlation Bank 1 A · P0524 Engine Oil Pressure Too Low · all OBD2 codes.
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