Since its invention in the late 1800s, diesel engines have become one of the leading pieces of machinery used across many industries today. First used for labor-intensive sectors like manufacturing and agriculture, diesel engines are now an integral part of the transportation industry. Not only does it give truck owners better fuel economy, especially with premium diesel, diesel engines are also more durable than their gasoline counterparts, which means they have a longer life span.

Because it is designed for heavy-duty tasks, it is vital for truck owners to regularly maintain their diesel engines to keep up the optimal diesel power performance. Diesel engines undergo significant stress, especially if used for towing or long-distance travel, which wears the engine's parts as time goes by. Among all crucial elements of a diesel engine, the piston rings are something truck owners should protect the most.

Uses of a Piston Ring

A diesel piston system consists of multiple piston rings with various functions that keep the engine running with no problems. The primary function of the first ring, known as the compression ring, is to completely seal the inside of the combustion chamber and maintain airtightness. This prevents gas leakage from happening, which usually causes problems in fuel consumption and exhaust gases.

If excess gas can penetrate the compression ring, the wiper ring can stop it from leaking to other piston parts. This ring has a taper angle face which wipes the gas when the piston moves to the crankshaft.

One other function of the piston rings is by controlling the oil that passes in the cylinder walls. The oil control ring needs to ensure that there is only a minimum amount of oil in the chamber walls to prevent entering the combustion chamber. This will keep the piston, combustion chamber, and engine from burning because of the high temperature inside the chamber.

Whether you are using a Duramax, Powerstroke, or Cummins truck, piston rings are one of the essential components of a diesel piston system. A failure in the piston ring will significantly decrease performance and damage other parts of the engine.

Causes of Piston Ring Failures

Because of the heavy workload that diesel engines go through, the piston rings receive tremendous pressure from the combustion chamber. This will initially cause the ring to fail to perform its engine functions. Apart from that, here are some other reasons that will affect your piston ring performance.

Inaccurate Assembly

One of the common causes of failures in the piston rings is if it is poorly assembled into the piston, especially the oil control ring. It might be because the rings are not adequately compressed or damaged during the installation process. There will be a noticeable upward bend on the broken side of the ring once it fails.

Improper installation of the piston rings can also cause significantly high crankcase pressure (blow-by) as it allows a combustion path to the crankcase.

Damage in Oil Control Ring

It is highly possible that the piston rings are damaged if it consumes an unusual amount of oil to function. Again, the likely cause of this is if the rings, particularly the oil control ring, are damaged while installing or using low-quality rings.


Due to dirt particles and poor oil quality, contaminated fuel will cause the piston rings to wear at a reasonably higher rate than usual. This might be because the rings were not properly cleaned before installation or if the air intake system leaks. Inadequate filtration causes the dirt to mix with the fuel and gas, bringing sludge across the combustion chamber, decreasing the ring's lifespan.

Symptoms of a Failing Piston Ring

Learning about what causes piston ring failures is essential for truck owners, but so is recognizing the truck's symptoms once it happens. Many truck owners ignore the signs of wear which leads to financial stress in the long run. Here are some indicators that you can check out to see if your piston rings need to be replaced.

Unusual High Oil Consumption

The standard for truck owners in adding oil to the engine is every 3,000 to 5,000 miles. So, if you are adding oil more often than usual, it is a sign that the rings might have a problem. Worn piston rings and oil leaks will cause the engine to consume more oil, so it is better to have a mechanic evaluate the piston rings as soon as possible.

Decreased Acceleration Rate

When there is damage in the piston rings, the engine will have less power because of less compression in the combustion chamber. This means that the truck will take a long time to accelerate once the driver puts their foot on the throttle to accelerate.

Excessive Exhaust Smoke

It is uncommon for diesel trucks to emit thick exhaust smoke, and if it does, it is typically because of a problem in the piston ring system. A truck with piston ring issues will have thick exhaust smoke with dark gray and blue colors. The leaking of excess oil causes blue-gray smoke.

Oil in the Air Intake

This happens because of a blow-by, or when the mixture of oil and air escapes the piston rings and creates pressure in the crankcase. Oily air intake will disrupt optimal airflow into the engine, affecting the truck's fuel economy.

Weak Truck Performance

Possibly the worst-case scenario for truck owners is when the truck loses all its power. Extensive wear and tear of the piston rings will not allow the driver to accelerate appropriately (as mentioned above), and the overall performance will be abysmal. This situation will happen if the owner ignores all the other symptoms above. The truck might need to be towed to reach the nearest mechanic shop.

Take Good Care of the Piston Rings

Like upgrading with various performance auto parts, proper maintenance of the diesel engine components, including the piston rings, will help bring out the best of your diesel truck. Knowing the common causes and recognizing the indications of a failing piston ring will save truck owners tons of time and money moving forward.

If you're looking for aftermarket diesel parts direct supplier, be sure to visit Pure Diesel Power. You can browse through their massive selection of diesel products, such as engine parts and diesel fuel additives. Contact us at 715-254-1833, email us at [email protected], or visit our website,

Read More: How To Check Injector Pump On 5.9 Cummins