6 Clear Signs of Low Engine Oil You Shouldn’t Ignore

Spotted the little oil can symbol on your dash? It signals that oil pressure has dropped or levels are dangerously low. Ignore it, and the engine's next step may be total shutdown.

In this article, you’ll learn which signs you should not ignore and what to do when you spot them.

Unusual Engine Sounds: Knocking or Ticking Noises

A healthy engine runs with a steady hum. Deviations from that, especially rhythmic knocking or high-pitched ticking, point directly to lubrication problems.

When engine oil levels drop too low, metal surfaces lose their protective barrier and begin grinding against one another.

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Friction Rises as Oil Falls

As shown in a 2019 study on lubricant impact, inadequate lubrication significantly increases friction across multiple engine components in a 3.6L production engine.

This spike in friction correlates consistently with noise generation and accelerated wear.

Metal-on-Metal Sound Clues

Ticking typically originates from the valve train—lifters or rocker arms that can't operate smoothly when oil pressure drops. Knocking, on the other hand, often emerges from deeper within the engine block. This low-pitched, repetitive thudding sound suggests rod knock, where pistons slap against the cylinder walls due to worn bearings.

Ticking noise: Usually faster, higher-pitched, often increases with RPMs—trace it to oil-starved lifters or valves.
Knocking sound: Louder, deeper, more ominous in tone—points to severe internal damage, especially if persistent.

Unusual Engine Temperatures?

With insufficient oil, the engine loses a critical cooling agent.

As temperatures climb, components like pistons, cylinders, and bearings expand abnormally, leading to inefficient performance or, in severe cases, component failure.

Coolant can’t compensate alone: While the cooling system handles external temperatures, oil manages internal hotspots. When oil runs low, even a functioning radiator can't fully prevent overheating.
Heat builds quickly at high speeds: Under load or during rapid acceleration, metal surfaces generate more friction. With too little oil to absorb and spread that heat, the temperature gauge can spike within minutes.
Engine shutdown risk: Some modern engines use safety shutdown protocols when they detect unsafe temperature levels. This isn’t a glitch—it’s a programmed response to avoid catastrophic damage when cooling fails.

Ever checked your temperature gauge and noticed it creeping higher than usual after a long drive or while idling in traffic?

Does Your Car Suffer From Poor Fuel Efficiency?

If your vehicle begins to consume noticeably more fuel but your driving habits haven’t changed, low engine oil could be behind the shift.

A 2019 study found that poorly lubricated engines showed a marked increase in Brake Specific Fuel Consumption (BSFC), a standard metric for engine fuel efficiency.

The study identified a consistent correlation between degraded or low oil and a noticeable drop in miles per gallon (MPG), strengthening the mechanical link between lubrication and fuel efficiency.

If the oil level is low, the engine struggles to maintain thermal stability, which increases fuel demand.
Oil with reduced viscosity loses its ability to lubricate, leading to drag losses and inefficient combustion.
Internal friction spikes when lubrication fails, causing the engine to operate outside optimised parameters.

That Lingering Burnt Smell?

When a sharp, acrid scent fills the car's interior, especially after driving for a few minutes, don't reach for the air freshener. This is often the result of engine oil leaking onto hot components, such as the exhaust manifold or cylinder head.

Engine oil in contact with high heat doesn't just evaporate quietly. It combusts in small patches, producing a distinct burning odour that seeps through vents and lingers within the cabin.

What to Do When You Notice It

Pop the hood and look for wet spots or smoke around the engine block.
Check for fresh oil beneath the car after parking, the spot might be small but unmistakable.
Take note of when and how often the scent appears, every drive, only on inclines, or only after hard acceleration?
Visit an automotive technician and ask for a pressure test or dye inspection to pinpoint the leak.

Still unsure what that smell actually indicates? Here's how Volvo breaks it down, from burning oil to electrical shorts to melting plastic.

Difficulty Starting Your Car? A Sign of Low Oil

Turning the key and hearing a sluggish crank or extended churning before the engine catches? That’s not just a battery issue. It can be a sign of low engine oil.

Cold Mornings, Thicker Challenges

Oil viscosity varies with temperature. On colder days, oil naturally thickens; combine that with low levels, and the engine faces a double burden. With insufficient oil pressure during cold starts, the lubrication system fails to protect sensitive parts like the valve lifters and piston rings from abrasive friction.

Oil fails to reach top-end components fast enough due to low pressure.
Hydraulic lifters may not actuate properly, disrupting timing.
The starter system compensates for sluggish ignition, leading to wear.

Hear a few extra revolutions before your engine fires up? That pause speaks volumes. It signals that oil isn’t doing its job fast enough, or more likely, there simply isn’t enough of it.

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How Often Does It Happen?

While data on engine start issues directly attributed to oil levels is limited, a 2019 survey by AAA revealed that mechanical engine failures accounted for over 20% of roadside service calls. Among those, hard starts during cold conditions were a common complaint, often linked to neglected maintenance.

Answers to Common Questions About Low Engine Oil

Do I have to worry about low car oil?

Yes. Low engine oil leads to increased friction between moving parts, which directly accelerates wear inside the engine. Without enough lubrication, metal components grind against each other and generate heat, increasing the risk of internal damage or total engine failure.

Don’t like to change car oil? See the costs of electric cars

What are the main signs of low car oil?

The most noticeable indicators include:

Illuminated Oil Pressure Warning Light: This light activates once oil pressure drops below the necessary threshold for safe engine operation.
Unusual Engine Noises: Knocking, ticking, or tapping sounds can indicate increased metal-to-metal contact due to insufficient oil.
Rising Engine Temperature: Oil helps with engine cooling; when it’s low, the cooling efficiency drops, leading to overheating.
Thick Smoke from Exhaust: A thin mist is normal, but blue or grey smoke often links back to oil burning inside the engine.
Stalling or Slow Acceleration: Without enough lubrication, engine parts lose synchronisation, disrupting normal operation.

What do I need to do when the oil is low?

Check the dipstick first.

If oil barely registers or appears dirty and thick, top it up immediately with the correct grade specified in your car's manual.

If the oil level drops again quickly or if new symptoms arise, like noise or overheating, a mechanic should inspect the system for leaks or damage.

Regular maintenance routines, including oil changes every 3,000 to 7,500 miles, depending on driving conditions and oil type, prevent most oil-related problems.