Why is my engine ticking?

An engine ticking noise, a light tapping that speeds up with the engine, most often comes from the valvetrain at the top of the engine: low oil, worn lifters or valve clearances out of adjustment. An exhaust manifold leak ticks too, loudest when cold. Fuel injectors tick normally. A deep knock from low in the engine is far more serious.

Updated November 3, 20264 minute read

Intake bucket lifter UK: Intake bucket tappet
Exhaust camshaft
Exhaust manifold
Fuel injector

Rendered from the app's 3D model.

The likely causes, most common first

Low or old oil
Most likely

How it shows A light ticking from the top of the engine, loudest at start-up and at idle, often with the oil change overdue.

Check With the engine off and the car on level ground, check the dipstick. Oil below the low mark, or black and thin, comes first.

Have it checked soon
Valve clearances out of adjustment or worn lifters
Common

How it shows A steady tick from under the valve cover that follows engine speed and does not fade as the engine warms.

Check A shop can measure the valve clearances, or on engines with hydraulic lifters, find the one that no longer pumps up.

Have it checked soon
An exhaust manifold leak
Common

How it shows A tick or a puffing sound that is loudest on a cold start and quiets as the metal warms and closes the gap, often louder as you accelerate.

Check With the engine cold, look for black soot around the joint between the exhaust manifold and the cylinder head, and for a cracked manifold or a broken stud.

Have it checked soon
A loose spark plug
Less likely

How it shows A sharp tick or puffing from one cylinder, sometimes with a misfire, often soon after the plugs were changed.

Check Have the plug checked for tightness. A plug that has pulled its threads out of the aluminum head needs the threads repaired.

Have it checked soon
A worn rod bearing
Less likely

How it shows Not a tick but a deeper, heavier knock from low in the engine that grows with speed and load, often after the engine ran low on oil.

Check Stop the engine and check the oil level. A deep knock from the bottom of the engine means do not drive it: have it towed.

Don't drive it

How to narrow it down

With the engine off and the car on level ground, check the oil on the dipstick and top it up to the mark with the oil the automaker specifies.
Note when it ticks: only for a few seconds after a cold start, all the time, faster as the engine speeds up, or only when you accelerate.
With the hood open and the engine idling, listen from the top of the engine and near the exhaust manifold, keeping clear of the belts and the fan and never touching the hot parts.
Look for black soot around the exhaust manifold's joints and for oil around the valve cover.
If it is a deep knock from low in the engine, or the red oil warning light comes on, stop the engine and have the car towed.

Is it safe to drive with an engine ticking noise?

Have it checked before you drive far

A light tick, usually, as far as a repair shop, once you have checked the oil. Many ticks come from low oil, and topping it up quiets them. Two things change that. The red oil warning light means stop the engine at once, and a deep knock from the bottom of the engine that grows with speed is a worn bearing. In either case, pull over when it is safe, switch off and have the car towed.

Is engine ticking normal?

Some is. Fuel injectors click as they open and close, a fast, light ticking like a sewing machine that every gasoline engine makes, and engines with direct injection tick louder still, because their high-pressure pump and injectors are louder. A brief tick for a second or two after a cold start, while the oil reaches the top of the engine, is normal on some engines too. A tick that is new, louder than it used to be, or that comes with the check engine light is worth having checked.

Why does my engine tick when it is cold?

Two causes stand out. An exhaust manifold with a cracked flange or a failing gasket leaks most when it is cold, because the gap closes as the metal grows with heat, so the tick fades as the engine warms. Hydraulic lifters that have bled down overnight tick until the oil pressure fills them again, and thick oil in winter takes longer to get there.

In the app’s engine each cam lobe presses on a bucket lifter over its valve, and the thickness of the bucket’s crown sets a small clearance. As that clearance grows with wear, the bucket taps on the lobe with every turn, a tick that stays whether the engine is cold or warm. The four-stroke engine guide shows the camshafts and valves at work.

Questions people ask

What is the difference between an engine tick and a knock?

A tick is light and quick, usually from the top of the engine: the valvetrain, the injectors or an exhaust leak. A knock is deeper and heavier, from low in the engine, and grows with load. A knock from a worn rod or main bearing means stop.

Can low oil cause engine ticking?

Yes, and it is the most common cause. With too little oil, or oil that is old and thin, the valvetrain at the top of the engine gets less of it and starts to tick. Topping up to the mark often quiets it, but find out where the oil went.