Why Do Diesel Engines Rattle When Old? [Quick Explanation]

Engine noise is a well-known problem for automobiles. It can scare the average joe that doesn’t know too much about cars. For the normal ear, these noises can be hard to distinguish as well. 

Diesel engines have been an important part of powering machines and automobiles for the longest time. These engines are favored because they are very efficient.

If you continue to play them off, some of the noises can mean the car needs fixing. It can save you a lot of trouble and money if you can hear when your vehicle needs a check-up. Continue reading below to see the different causes of the rattling of a diesel engine. 

The Diesel Engine’s Function

Diesel engines are different from gas engines in terms of fuel combustion. Gas engines use spark plugs that utilize electricity for their fuel combustion system. This difference in function is why cars that run on gas tend to be quieter than diesel cars.

On the other hand, diesel engines use pistons and air compression. When air is compressed, its temperature rises, and when it is hot enough, the fuel is exposed to it. This creates the combustion of fuel in the engine.

The clatter you might hear in diesel engines may be a result of fuel not properly burning. This is mainly because of the fuel not being pure and having the slightest bit of contamination.

It doesn’t mean that if it clatters, it is a bad sign for your engine because it is supposed to do that. It might just warrant a few bad glances and comments from nearby people who would get annoyed. 

The Different Noises and What to do When Heard

If you listen closely, different noises can come from the hood of your car. It is important to know what noises mean because some sounds should happen. 

Frequently Asked Questions

What does a rattling sound mean in diesel engines?

Rattling can usually be heard when the vehicle is accelerated. Diesel takes longer to heat up than gasoline. When you accelerate the vehicle, there is a tendency for the hot air and fuel to come into contact prematurely. 

This results in the diesel fuel not burning efficiently. It is more commonly known as pre-ignition, which can harm the engine’s pistons, connecting rods, and valves. 

When this sound is heard, you might want to consider changing fuel because that is what causes it. Another cause could be the belt tensioner which is responsible for applying and maintaining tension in the engine. 

What does a ticking sound mean in diesel engines?

Ticking noises are because of valves, pushrods, or pistons. It may mean a lot of things, such as wrongly-adjusted valves, a low level of oil, or a noisy lifter. 

You should first check the oil level when you hear this ticking sound. Low oil levels mean that the engine’s valves do not get the proper lubrication it needs. When this happens, you need to service your vehicle as soon as possible. 

A bigger problem is if it’s a damaged lifter or a lousy connecting rod. It means that the motor needs to be rebuilt. 

What does a knocking sound mean in diesel engines?

The fuel injectors create the main culprit for a diesel engine’s knocking sound. Lubricants can lessen these sounds, but a second look is still recommended. If the sound is still present after around 20 minutes, it might mean something is wrong.

Knocking is a sound that may not be a reason for alarm. Usually, knocking just means improper lubrication of fuel injectors.

What does a meshing sound mean in diesel engines?

The timing chain connects the crankshaft and camshaft. This chain must be maintained all the time. A junky timing chain may cause a meshing sound in the engine. 

Meshing sounds mean that the chain is loose. A loose timing chain has the possibility of tearing off and further damaging the engine. It can cost a lot of money to fix this problem when it happens.