The oil pump is a critical component in any engine that circulates oil throughout the lubrication system. It draws oil from the oil pan and pushes it through the oil filter and various galleries to lubricate the critical components of the engine. A failing or faulty oil pump can lead to severe engine damage if oil is not provided to the necessary areas. Being able to recognize the signs of a failing oil pump can help prevent catastrophic engine failure. In this article, we will go over the function of the oil pump, the signs of pump failure, and steps to take if you suspect your oil pump is having issues.
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What Does the Oil Pump Do?
The oil pump has one major function – to circulate pressurized oil throughout the engine and maintain oil pressure. Here are some key points about what the oil pump does:
- Draws oil from the oil pan and intakes it into the pump
- Uses impellers, gears, or rotors to pressurize the oil
- Forces pressurized oil through the oil filter and galleries
- Maintains adequate oil pressure throughout the engine (normal is 30-80 psi depending on engine speed)
- Supplies a constant flow of oil to critical components like bearings, piston skirts, timing chains, valvetrain, etc.
- Returns oil to the pan where it cools and carries away contaminants
The oil pump is a mechanically driven pump that relies on engine speed to determine its output. At low engine speeds, the oil pump spins slowly and oil pressure is lower. At higher speeds, pump output and pressure increase proportionally. The pump must maintain the minimum oil pressure required for safe operation at all engine speeds.
Signs of a Failing Oil Pump
There are some common signs that can indicate your oil pump is failing and should be inspected or replaced:
Low Oil Pressure Warning
The most obvious sign of a bad oil pump is if the low oil pressure warning light comes on your dashboard. This light is illuminated when oil pressure drops below the minimum psi needed for safe operation – usually around 5-10 psi. Don’t ignore this warning light – it means oil is not circulating properly and engine damage can occur rapidly.
Low Oil Pressure Gauge Reading
Many vehicles are equipped with an oil pressure gauge that displays a live reading. Oil pressure should be 30-80 psi depending on engine speed, operating temperature, and engine load. Consistently low readings below the normal range can indicate pump wear or failure.
Knocking or Ticking Noise from Engine
If critical components like lifters, camshafts, rocker arms, and timing chains are not getting adequately lubricated they can make knocking or ticking noises. Don’t confuse normal injector noise with abnormal sounds indicating insufficient oil delivery.
Excessive Engine Noise on Startup
When you first start your engine, a few seconds of louder noises are normal as oil circulates and provides lubrication. But excessive engine noise after startup for more than 5-10 seconds can mean oil flow is delayed or restricted.
Rough Idle, Loss of Power
Poor oil supply affects engine performance. You may notice rough idle, stalling, or loss of power under load. This can indicate wear from inadequate lubrication.
Oil Leaks
Look under your vehicle – are there any new oil leaks? A bad seal or gasket on the oil pump can cause external oil leaks. Oil may also leak through compromised oil galley plugs if pressure is too high.
Sludge in the Oil
If you check under the oil cap or dipstick and see thick, tar-like sludge, it can be caused by oil breakdown from excessive heat and blow-by gases due to insufficient oil delivery.
Drop in Oil Level
If your oil level is going down rapidly between oil changes, it may be an indication of internal wear and increased oil consumption caused by poor lubrication.
Discolored Oil
Do a visual inspection each time you check your oil. Oil should be clean and light amber/brown. If it is dark, murky, or milky looking it can mean water contamination or excessive debris from internal wear.
What Happens When an Oil Pump Fails?
If an oil pump completely fails the consequences will be catastrophic. Without circulating oil, there is nothing to prevent severe friction, heat buildup, and direct contact between metal components moving at high speeds. Here is what will happen:
- Bearings will seize from friction and overheating, possibly welding themselves to the crankshaft or camshaft
- Piston skirts and cylinder walls will contact without lubrication causing scuffing and scoring damage
- Timing chains or belts will stretch and wear without oil, causing cam, crank, and valve timing issues
- Rocker arms will grind aggressively into cam lobes and valve stems, damaging both
- Turbocharger bearings will overheat and seize
- Heat buildup can cause pistons to scuff or seize against cylinder walls
- Excessive heat generation can lead to thermal expansion damage and engine seizure
This level of mechanical damage usually requires a complete engine overhaul or replacement. That is why immediate action should be taken if oil pump failure is suspected.
Steps to Take if Oil Pump Failure is Suspected
What should you do if you have signs of a failing or failed oil pump? Here are the recommended steps:
Safely Pull Over and Shut Off Engine
If your oil pressure light is on or you hear knocking noises from low oil pressure, safely pull over and shut off the engine immediately. Continuing to run risks total failure.
Check Oil Level and Quality
Pop the hood and check oil level at the dipstick. Also look at oil condition – is it very dirty or have fuel contaminants? Adding oil or changing contaminated oil can temporarily help limp home IF damage has not already occurred.
Do Not Restart Engine
Do NOT attempt to restart the engine unless your oil pressure gauge confirms there is adequate pressure over 10 psi. You may have enough oil to get home but restarting without oil pressure risks total failure.
Tow Vehicle to Service Shop
The only safe option is to have the vehicle towed to a repair facility for diagnosis. Technicians have tools to accurately measure oil pressure and determine if the pump, filter, or pressure relief valve have failed.
Repair or Replace Oil Pump
If the oil pump is confirmed to be defective, replacement or rebuilt pump installation will be required. All internal engine bearings, seals, and gaskets should be inspected for wear damage.
Perform Full Engine Diagnostic
A full engine tear down may be recommended to check all critical components like bearings, piston skirts, cylinder walls, valve train, etc. for damage from oil starvation. Repairs can be made or engine replacement may be required.
Check for Underlying Issues
Diagnosing what caused oil pump failure is important. Low oil level, sludge buildup, wrong weight oil, and overheating can all be contributing factors. Address any underlying issues during repairs.
Preventing Oil Pump Failure
Oil pump problems don’t happen without some underlying cause. Here is how to help maintain your oil pump and prevent failure:
- Use only recommended viscosity and quality oil for your engine and operate within a normal temperature range.
- Follow the manufacturers oil and filter change intervals to prevent sludge buildup.
- Watch for leaks and fix any external oil leaks from the oil pump seal/gasket, valve covers, etc.
- Don’t overfill or underfill your oil level – stay within the proper range.
- Make sure to warm up the engine gently and avoid high RPMs until full oil pressure is achieved.
- Consider installing an oil pressure gauge to monitor real-time values and trends.
- Address any new engine noises, oil leaks, or performance changes immediately.
Proactive oil pump maintenance and early issue detection is much less costly than waiting for total failure to occur.
Conclusion
The oil pump is the heart of the lubrication system and must perform its job to maintain engine operation and durability. Telltale signs like low oil pressure warnings, knocking noises, performance issues, and leaks offer clues that your oil pump may be failing. Address these issues immediately to potentially avoid catastrophic engine damage. With oil pump replacement, engine inspection, and addressing underlying problems, costly repairs can be averted. Proper maintenance and early problem recognition are key to prolonging the life of your oil pump.