Car Has Oil Pressure Issues – Causes, Symptoms & Diagnosis

If your car shows low oil pressure, fluctuating pressure or an oil pressure warning light, the engine may not be receiving proper lubrication. Oil pressure issues can be caused by low oil level, a failing oil pump, clogged pickup screen, worn bearings or faulty sensors. This guide explains the most common causes and how to diagnose the issue accurately.

Symptoms

• Oil pressure warning light
• Ticking or knocking noises
• Fluctuating oil pressure gauge
• Engine overheating
• Burning oil smell
• Reduced engine performance

Main Causes

• Low oil level or oil leak
• Failing oil pump
• Clogged oil pickup screen
• Worn engine bearings
• Incorrect or old oil
• Faulty oil pressure sensor
• Clogged oil filter

Step‑by‑Step Diagnosis

1. Check Oil Level

Low oil level is the most common cause of oil pressure issues. Inspect the dipstick and look for leaks.

2. Inspect for Oil Leaks

Check around:

• Oil pan
• Valve cover gasket
• Oil filter housing
• Front and rear main seals

3. Check the Oil Pressure Sensor and Circuit

A sensor or circuit fault can trigger an incorrect warning. Compare available sensor data with a mechanical oil pressure measurement before replacing the sensor.

4. Inspect the Oil Filter

An incorrect, damaged or severely restricted oil filter can contribute to lubrication problems. Check the filter type, condition and installation as part of the diagnosis.

5. Check Oil Pump Operation

A failing pump cannot maintain proper pressure. Symptoms include:

• Low pressure at idle
• Pressure drops when warm
• Engine noise increases

6. Inspect the Oil Pickup Screen

Sludge buildup can block the pickup screen, starving the pump of oil.

7. Check for Worn Bearings

Excessive bearing clearance reduces oil pressure and causes knocking noises.

Relevant Fault Codes

• P0520 – Engine Oil Pressure Sensor/Switch Circuit
• P0521 – Engine Oil Pressure Range/Performance
• P0522 – Engine Oil Pressure Sensor Low
• P0523 – Engine Oil Pressure Sensor High

When Is a Diagnostic Scanner Useful for Oil Pressure Problems?

A diagnostic scanner can help read oil-pressure-related fault codes and, on supported vehicles, display oil pressure sensor or switch data.

However, scanner data does not confirm actual engine oil pressure. If low oil pressure is suspected, the pressure should be verified with the appropriate mechanical test equipment before the vehicle is driven further.

Compare Diagnostic Scanners →

When to Seek Professional Help

• Oil pressure warning light stays on
• Engine makes knocking or ticking noises
• Oil pressure drops when warm
• Oil pump suspected to be failing
• Metal shavings found in oil