An engine is a complex machine with dozens of moving parts. The shafts, valves, pistons, and belts that move around under the hood can make a noise. Aside from an engine’s uniform rumble, many modern vehicles have a fuel injector pump that makes a ticking sound, which stems from the pump rapidly opening and closing.
Another type of ticking or clicking can occur when the engine is cold. An engine clicking noise after a cold start can occur because the cold oil hasn’t properly reached all the engine’s nooks and crannies. Hence, some components will make metal-on-metal contact and create sound. However, this sound will disappear once oil lubricates the engine when it warms up.
That said, an engine can develop an unusual ticking noise that could mean it has an issue that needs to be resolved. Here are some of the most possible causes for an engine that has an unusual ticking noise:
Low oil pressure or levels can deprive engine components like valves and lifters of oil. When this happens, the metal-on-metal contact can create tapping or ticking noises. This noise might occur during a cold start. However, it shouldn’t persist for long. Low oil pressure is a serious issue since it can cause your engine to overheat and wear out rapidly.
The exhaust manifold is the piping that facilitates your engine’s exhaust gases after they exit the engine. If the exhaust manifold is cracked or leaking, it’ll create a loud hissing or tapping sound. This sound typically comes from underneath your engine.
Misaligned cam lifters or valves can create a metallic rattling or tapping noise. This sound can be similar to an engine’s fuel injection system.
Piston connecting rods are the components underneath the pistons that connect them to the crankshaft. When these rods wear out, they can make noise, which means a rod hits the crankshaft as the rod changes direction. This part makes a knocking noise that increases in volume and intensity when accelerating.
This is a serious issue because the connecting rod is a critical engine component. If ignored, the faulty rod can damage other internal engine components and require an expensive rebuild.
Bad spark plugs won’t properly ignite the air-fuel mixture in the combustion chamber. When this happens, your engine will misfire, resulting in an audible ticking or tapping noise under the hood.
The engine uses the serpentine belt to power components like the A/C compressor, power steering motor, and alternator. Over time, the bearings in the pulleys can wear out and create a ticking noise. Alternatively, the components powered by the serpentine belt can also have issues and make noise.
The engine fan or radiator fan can make a ticking noise if its plastic components get damaged or if the fan has nuts that have gotten loose. Sometimes simply tightening some bolts will solve the issue. But a damaged fan blade or motor will require a replacement.
The first step in any repair is identifying the main cause of the issue. This can be quite challenging since identifying where the source of the sound can be tricky.
That said, certain issues tend to have a characteristic sound. A problematic valvetrain or an engine that lacks oil tends to sound more metallic than a leaking exhaust manifold, which makes more of a whooshing noise. You can research what each issue sounds like by searching for videos on the internet. Alternatively, you can consult with a mechanic. Once you know the problematic part, these are usually the fixes for these issues:
Replacing the oil and oil filter is the solution if your ticking noise is caused by low or contaminated oil. Sometimes, your engine might need special additives, since these can fix issues like engine noise caused by a faulty valve lifter. Owners should also check oil pressure since some problematic engines will show high or low oil pressure.
Inspecting the camshaft, pushrods, and rocker arms for proper alignment is a common fix for ticking noises from an engine’s valvetrain. This inspection checks the parts’ clearances and adjusts the screws in the rocker arms.
Replace worn-out or damaged components like exhaust manifolds, pulleys, connecting rods, and spark plugs. Replacing spark plugs is an easy DIY process since it only involves a few tools. However, replacing other components like exhaust manifolds and connecting rods will involve disassembling engine components. If you aren’t confident in your DIY skills, it might be best to leave the task to a trusted mechanic.
Remember that some ticking sound in your engine when idling and accelerating is normal. However, a problem can create a different noise. You should be familiar with the sound of your engine so that you’ll be able to sense if a part has failed.
Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.