Are Ticking Engine Noises a Warning? Or Just Annoying?

If the ticking noise occurs after your engine turns off, there probably is no cause for concern. Many car parts “de-energize” long after the motor stops. Those ticking sounds are infrequent and have different pitches.

In addition, many cars have heat shields around and under the engine. Once the engine turns off, you might hear a tick or two as the shields cool down. If you hear these ticking sounds only after the engine turns off, you typically are in good shape.

Why Is My Engine Ticking?

There are several reasons for more persistent ticking sounds. These questions might help pinpoint the cause of the distressing noise.

• Is the ticking consistent or does it vary with the engine speed or rpm?
• Does it happen consistently, or only after the engine warms up?
• Does it only occur when the car starts?
• Can you lift the hood and determine what part of the engine the sound is coming from?

Bearings

Anything connected to a serpentine belt (or pulleys) could have a bearing. When these bearings wear out, they frequently emit a ticking sound, especially when the car accelerates. Usually, you can just replace the bearing, though sometimes the entire part (like a water or power steering pump) could need repair.

Exhaust Leak

Though it sounds like an engine ticking, the sound of an exhaust leak comes from under the car’s chassis. If an exhaust part develops a leak, you hear the gasses pulsate. With the engine idling and parked, get down low and listen for an exhaust leak near the plumbing parts. You might see or hear the gas escaping or see a heavy black residue near the leak. Usually, these leaks are easy fixes.

Fuel Injectors

Fuel injectors can become dirty with grime building up along these parts. The dirt can cause the flow of fuel to be restricted, impact fuel economy, and cause ticking. A dose of fuel injector cleaner or removing them for a professional cleaning can eliminate that tick.

Fuel Pump

Most fuel pumps are located in the fuel tank. The fuel insulates the pump, keeping it cool and quiet. If you are in the habit of running the fuel tank to fumes, you might be hearing that pump. Fill up the tank to full, and see if the noise disappears.

Lack of Oil

One major cause of engine ticking noises is a lack of lubrication. If you suddenly hear a tick, check your oil pressure gauge and examine your oil dipstick to verify you have enough oil. While you have the dipstick out, check how clean the oil is. Dirty, sludgy oil does not lubricate your car’s parts as well as fresh oil. Keep the car filled with oil and change it as the owner’s manual recommends.

Piston Slap

For some engines—especially those with an aluminum block—when starting the engine, you might think you inherited a diesel engine. It could be piston slap. When the engine is cold, some pistons have slack as they slide up and down the cylinder walls at startup.

As the engine heats up and parts expand, that slack disappears, and the piston has less room to wiggle. It can be annoying, but short of replacing the pistons, there is little remedy for piston slap.

Radiator Fan

Most radiator fans have a  surrounding shroud, making the fan more effective. But if twigs or road debris get kicked up under the car, they might lodge against the fan blades and rhythmically knock with each blade revolution.

With the engine off, check the radiator fan for any obstruction. If you notice one, disconnect the car’s battery before dislodging the offending material, so the electric fan doesn’t turn on and strike your hands. While looking, also check the pulley belts to see if a belt is rubbing against a car part or other debris.

Rod Knock

A rod knock is loud and increases with engine rpm. The connecting rods are connected to the crankshaft. If a rod gets bent or worn out, it gets out of alignment with the crankshaft. This must be repaired quickly, and the car must be towed—not driven—to a shop. Ignore this tick, and the entire engine might become a wreck.

Mechanic’s Stethoscope

A mechanic’s stethoscope makes it easier to identify the source of the engine ticking. If you hear other noises from your car, they might be warning signs of a potential problem. Don’t just crank up the stereo. Determine what is causing the ticking noise and fix it before a little problem becomes a major headache.