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What Is A Good Oil Additive For Diesel Engines?

Featured image for "What Is A Good Oil Additive For Diesel Engines?" blog post. Large yellow dump truck.

Can a diesel motor oil benefit from a motor oil additive? In some cases, utilizing a good quality engine oil additive can bring the owner/operator significant benefits. In this blog post, we’ll try to provide some insight as to what is a good oil additive for diesel engines.

Due to today’s stiff environmental emissions regulations, modern diesel engine motor oils are forced to perform under extreme operating conditions. Conventional motor oils from only ten years ago would be ill equipped to handle the extreme operating conditions of today’s modern diesel engines. Traditional lubricant manufacturers continue their struggle in trying to meet these stringent EPA regulations.

Today’s conventional diesel engine oils are made up of various additives that help protect critical internal parts of the diesel motor. The following are some of the additives that play an important role in the performance of a diesel motor oil.

Viscosity Improvers

VI Improvers are called polymers. Think of them as very small or miniature coils, which are so small they can only be seen under a microscope. These miniature polymer coils are actually giants when they are asked to perform.

During cold temperatures, these polymers “coil up” so that the lubricant can flow easily in extreme cold temperatures. During extremely hot operating conditions, the polymer then “uncoils” to slow down or hinder the oil molecules more and more, thus not allowing the oil or the viscosity to thin down. Visualize that at low temperatures, the engine oil is less thick and during extremely elevated temperatures, the oil is less thin.

These polymer coils give an engine oil its desirable characteristics. Over time, viscosity improvers or polymers tend to shear out. In other words, the coils are literally cut up over time. When this shearing happens, the motor oil slowly loses its multi-viscosity, multi-temperature characteristics. When deciding what is a good oil additive for diesel engines, look for an oil booster that contains quality shear stable viscosity improvers.

John Deer heavy duty diesel tractor.
Diesel engine oils operate in extreme conditions that can cause a loss in viscosity.

Neutralizes Acids

Diesel engines are exposed to a large amount of acidic compounds. Some diesel engines will suck in up to 16,000 gallons of air per minute. Air is made up of 60% nitrogen, and because of all the nitrogen found within those 16,000 gallons of air, acidic compounds can form.

The burning of diesel fuel creates these corrosive acids which can cause undue wear unless they are neutralized. It is therefore very important that a diesel engine oil have the ability to neutralize acids and control corrosion. When looking at a diesel engine oil’s technical data sheet, you will notice a spec called TBN or Total Base Number. This number indicates how well the particular diesel engine oil fights acid and its corrosive effects.

The higher the TBN number, the more effective it is at fighting acids and corrosion. Many commercial diesel engine oils show TBN ranges anywhere from 6 to 10 TBN. Through constant use, the Total Base Number starts to diminish and lose its ability to fight acids and corrosion. Another important parameter when deciding what is a good oil additive for diesel engines would be to choose an engine oil additive that can boost the TBN, thus helping to neutralize harmful acids.

Long diesel fuel truck.
The fuel burned by diesel motors cause acids to form. Diesel motor oils must be able to neutralize these destructive acids.

Provides Cleanliness

Modern diesel motor oils must have a chemistry that can control and deal with increased soot levels and other contaminants. Additives called detergents and dispersants are utilized in helping a diesel engine oil to control soot thickening sludge and varnish. These detergents and dispersants keep these contaminants suspended in the oil so that they can be filtered out. When a quality motor oil additive is added to a conventional diesel motor oil, it should help in cleaning and maintaining cleanliness in the engine.

Red diesel dump truck.
Knowing what is a good oil additive for diesel engines and using it in your equipment can help maintain engine cleanliness.

Control Wear

One of the main objectives for a diesel engine oil is to protect all the internal parts it comes in contact with. A diesel engine oil is made up of base oils and carefully selected additives that must work together in controlling contaminants and acids, helping to cool the engine, and protecting all parts from friction and wear. Slowly but surely conventional diesel motor oils start to degrade and lose their effectiveness in combating the myriad of issues they were designed to perform.

As the oil is exposed to acids and high temperatures, the important base oils and additives become weaker. To slow down this downward spiral, utilizing a high performance oil additive can vastly boost an engine oil’s lifespan and performance. Adding a diesel engine oil additive will help a diesel motor oil keep temperatures cooler, help to reduce engine wear, provide enhanced acid neutralization, keep piston ring deposits to a minimum, reduce engine oil consumption, minimize piston scuffing, improve compression, protect against rust and corrosion, boost viscosity, and reduce downtime.

A quality engine oil additive can enhance a motor oil's ability to reduce friction and wear.
A quality engine oil additive can enhance a motor oil’s ability to reduce friction and wear.







There are many demands placed on diesel engine oils. Sometimes the demands are too great for conventional diesel motor oils to handle. Knowing that there could be a way to improve your diesel engine’s protection inspired you to ask the question in the first place: what is a good oil additive for diesel engines? Hopefully, this blog post provided some basic insight and answers to this question.