What You Need to Know About The New Diesel Engine Oils Standards

What You Need to Know About The New Diesel Engine Oils Standards

Attention fleet managers and mechanics:

Are you familiar with the new diesel engine oils standards that have been in place since December 2016?

These diesel engine oils standards that have just come down the pike could affect your business in a big way.

Some areas of the fleet management industry the standards will impact include diesel exhaust management, diesel engine maintenance, fleet management and upkeep.

In this post, I’ll provide you with detailed information about the following:

  • The new diesel engine oil standards in place from the API
  • The diesel engine oil categories vehicle owners and businesses need to comply with
  • The changes between the new and the old categories industry professionals like you need to know

I’ll also discuss the benefits: how the oil categories will impact performance and fuel efficiency, and the key differences between the diesel engine oils categories (CK-4 and FA-4) you need to know to operate your business vehicles.

Let’s get right down to it.

The Development of Two New Diesel Engine Oil Categories

After five years of development, the API (American Petroleum Institute) officially released the final approval of two brand new diesel engine oils, CK-4 and FA-4 to the trucking industry.

These two new categories were developed to comply with Phase Two of the EPA’s greenhouse gas emissions rules to protect the environment and produce cleaner air.

After half a decade of discussion between the American Petroleum Institute, oil marketers and additive suppliers, the new categories were finally approved and introduced.

It’s been a long time coming.

There hasn’t been a change in 23 years.

This is the first time since 1994 that there will be two different diesel engine oil categories.

These categories are CK-4 and FA-4.

Both diesel engine oils categories are said to:

  • Enhance engine performance
  • Provide better fuel economy for on-highway trucks with lower HTHS viscose formulas
  • Be better for fuel emissions.

But there are major differences between the two categories.

First CK-4.

CK-4 Diesel Engine Oils

The CK-4 diesel engine oils replaced the CJ-4 oils that you might be using now. But don’t stress: CK-4 diesel oil is backwards compatible and can be used with vehicles that take CJ-4 grade oils in most cases.

You’ll need to refer to your equipment vehicles user manuals and your engine manufacturer’s requirements to learn the specifications of your engine.

The newer categories provide fleet management industry professionals with some added benefits.

Some of these benefits of the new CK-4 compared to CJ-4 include better oxidation resistance, aeration control and shear stability.

Let’s discuss some basics of oxidation, oil aeration and shear stability.


Oxidation is a chemical reaction that occurs when the lubricant hits the air.

When oxidation is unstable, it causes problems such as varnish, sludge, sediment formation, corrosion and the heightened elevation of viscosity.

There are a variety of conditions that influence oxidation stability, including high temperatures, acids, liquids and alloys.

Oil Aeration

Aeration is the interaction between oil and air.

Air shows up in lubricating oil in three ways: as dissolved air, air bubbles and foam. When air bubbles rise above the surface, they transform into foam.

Aeration in an engine is influenced in three ways: by the speed of an engine (how fast the crankshaft speeds), oil level, temperature and engine design.

When oil levels are too high, temperatures are too hot and the engine is moving too fast.

The circulation of oil is affected and the engine compromised, causing loss of precision control, vibration, filter blocking, pump cavitation and loss of head in centrifugal pumps.

Shear Stability

Shear stability is the measurement of oil resistance influenced by viscosity when an engine undergoes high pressure.

High pressure takes a toll on your engine areas such as the pistons, oil pump and camshaft.

The lower the viscosity value, the better the resistance becomes when subjected to mechanical stresses or shear. Areas affected by shear stability include the piston rings, the oil pump and the camshaft.

The Differences Between CK-4 and FA-4

In spite of the above benefits, CK-4 won’t be used in newer equipment vehicles.

CK-4 diesel oil will only be poured into older truck engines, medium duty vehicles, vocational trucks, pickups and off-road vehicles.

On one hand, CK-4 categories work well with the medium duty vehicles and older truck engines, but they can’t be used in newer vehicles and newer heavy weight trucks.

Why is this so? The reason is that these truck engines weren’t build to take diesel oils that contain thinner viscosity levels or high temperature, high shear levels.

FA-4 Diesel Engine Oils

On the other hand, FA-4 diesel engine oil won’t operate with older on-road vehicles because of the oil’s low viscosity grade.

This inhibits the older model’s vehicle’s performance. They don’t perform well with the FA-4’s lower viscosity diesel engine oil grades.

This means, of course, they’re not backwards-compatible.

FA-4 was created for current diesel standards and for the design of upcoming vehicles predicted to be designed and built in the future.

FA-4 lubricants are a major part of the shift towards better fuel efficiency. The move is going in the direction of reducing fuel emissions in the fleet management industry.

The key benefits for fleet owners with newer vehicle models are simple: FA-4 diesel oils typically provide an additional 0.5% to 1% fuel economy benefits.

This is influencing oil markets big time.

For OEM’s: FA-4 brings new opportunities to meet fuel economy objectives and new vehicle engine engineering can benefit from lower viscosities without compromising the protection of vehicle engines.

For oil marketers: FA-4 offers a new roadmap to address the demand of a new market and expand the scope and reach of a new market need.

For fleet managers and mechanics: FA-4 diesel engine oils mean lower maintenance costs and lower operating expenses, which enables you to increase revenue and satisfy stakeholders and employers.

The Takeaway

The new engine oil standards seem to benefit everyone across the board:

  • They provide better fuel emissions for the environment
  • They offer ways for the fleet industry to save on operating costs
  • They enable businesses with older model vehicles to keep engines running

With the on-highway market using about 37 billion gallons of diesel every year, if we could save just 1%, it would equal one million gallons of fuel saved in a day.

What’s your point of view on the new diesel engine oils standards?

Leave it in the comments.

Our company provides pure heavy duty engine fluids for the commercial and industrial fluid applications. Contact us today to learn more about our product lines.

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