Diesel Engine Ticking Noise — Causes and Fixes

Hearing an engine ticking noise while hitting down the road can be a nerve-wracking experience. What’s more challenging and unnerving is trying to find the root cause of the problem.

Several issues can cause diesel engine ticking noise while idling or driving the car. Some of such issues are low or dirty motor oil causing improper lubrication, faulty fuel injectors, bad glow plugs, sticky valve lifters, or other worn-out engine parts. It can even be there’s nothing wrong with the engine — diesel engines typically have loud sounds.

ticking noise in diesel engine when idle

What Causes the diesel engine to make ticking noise?

Ticking and knocking noises from your engine are some of the noises that will scare the hell out of you. And when you hear these noises, something is probably wrong with the engine. Let’s have an in-depth look at the common causes of ticking noise in diesel engine when on idle or driving.

Low or dirty motor oil

Low or dirty motor oil is one of the most common reasons for diesel engine ticking noise while idling. Motor oil serves two essential roles — cooling and lubricating internal engine parts. If the oil is low, it will not do its job effectively. And if it accumulates dirt over time, it’ll lose its lubricating properties. As a result, the engine will emit a ticking noise as you idle or rev it.

Faulty fuel injector

Generally, faulty fuel injectors are the common cause of ticking noise in diesel engines when accelerating or idling. If there’s a fuel leak, mechanical problems, or the injectors are not sending the appropriate amount of fuel needed in the combustion chamber, it will cause a ticking, clicking, or knocking sound along with engine misfires.

Faulty glow plugs

Diesel engines use a small device called glow plugs instead of spark plugs. Aside from serving as spark plugs, these plugs cushion the sound generated in the combustion chamber. If the glow plugs become faulty, they will no longer cushion the noise produced in the combustion chamber. Invariably causing diesel engine ticking noise when idling or driving.

The engine is old.

Under perfect conditions, diesel engines are louder than gasoline engines. And the noise becomes more louder when the engine ages with mileage. For instance, a high-mileage diesel engine will make more than one that has barely hit 25,000 miles. So, the loud ticking noise from diesel engine you hear could be a result of old parts trying to work in unison with each other.

Worn or sticky lifters

Valve lifters are crucial engine components that regulate the valve timing in gasoline and diesel engines. If the valve is worn or sticky, it will cause ominous ticking or tapping sounds from the engine.

If you ignore the diesel engine ticking noise when cold or hot caused by worn or sticky lifters, it can damage the cam follower or the entire engine. Hence, you must clean or fix lifter issues.

Rod knocking

While not common, a connecting rod in your diesel engine can fail — causing diesel knock at low rpm or when accelerating. If the bearing on the space that connects the rod to the crankshaft wears out, the connecting rod will knock around, causing the ticking or knocking noise you hear.

There’s no easy fix solution for this problem. You are surely going to rebuild the engine. The sooner the better — ignoring it for an extended period will cause severe engine problems on other components like the crankshaft and the cylinder walls.

You are not familiar with diesel engines.

It could be there’s nothing wrong with the engine. You are just not familiar with diesel engine sounds. If you have been around petrol cars for so long and later acquired a diesel engine truck, you may think the unique sound in diesel engines when accelerating and idling is an issue. C’mon boy, you need to get familiar with the noise.

How do I stop my diesel engine from ticking?

The best way to stop a ticking noise on your diesel engine is to diagnose the engine and address the root cause of the problem. In a best-case scenario, you could have a low or dirty engine oil. In such a case, changing the oil is all you need to fix the problem.

However, in ugly scenarios, you could have bad lifters or bad connecting rods. Fixing them requires technical know-how, so you need to visit your mechanic. In some cases, the problem may require engine rebuild.

Frequently Asked Questions — FAQs

Is it normal for a diesel to tick?

Diesel engines have a unique sound different from gasoline engines that can be mistaken as a ticking or knocking sound. They are ignited by temperature and high pressure inside the combustion chamber instead of sparks from spark plugs. The unique ticking noise in a diesel engine is because the fuel is not burning evenly as they do in gasoline engines.

However, it is essential to note that a loud ticking noise in a diesel engine is a threat and you should treat it as a matter of urgency.

Can fuel injectors cause ticking?

Dirty or bad fuel injectors can cause engine misfires, leading to a ticking noise in your engine. Misfires happen when the air-fuel mixture in the combustion ignites at the wrong time or fails to ignite properly. This causes a sudden engine loss of power and ticking noise.

Can exhaust leak make ticking noise?

Exhaust leaks can cause a ticking noise like a musician’s metronome, especially when you start the engine in the morning. Broken exhaust bolts, holes in the exhaust neck, or anywhere in the exhaust pipe will allow air to seep out, creating that loud ticking noise.

Can the intake manifold cause a ticking sound?

It is unusual for an intake manifold to cause a ticking sound in the engine, but it does happen, anyway. A leak in the intake manifold will allow unmeasured air to enter the combustion chamber, causing too much air in the engine. The unmeasured air will throw the air-fuel mixture off balance, leading to engine misfire causing a ticking noise in the engine.

Can a head gasket make a ticking noise?

When a head gasket fails, the pressure in the combustion chamber will not be at the predefined level. Since a blown head gasket will cause improper sealant between the engine block and the head cylinder, the combustion of the air-fuel mixture will be limited. As a result, the engine performance will reduce and you may hear a ticking noise — an indication of a blown head gasket.

Final Words

There are several reasons why you could be hearing diesel engine ticking noise when driving or idling your truck. Rod knocks, sticky or bad lifters, faulty glow plugs, lousy fuel injectors, old engine parts, and low or dirty engine oil — causing lack of lubrication are the common causes of ticking noise from a diesel engine.

While diesel engines are much louder than gasoline engines, do not ignore any unusual sound from a diesel engine. The ticking noise could be a sign that something isn’t going well in the engine, and ignoring it for long will cause catastrophic damage.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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