Fleet managers have a tough job. Managing a vehicle fleet with heavy-duty and light-duty trucks and machinery is no easy task. Each vehicle has its own unique maintenance and lubricant needs. Fleet managers must develop a maintenance and lubricant strategy that considers each vehicle’s needs and the organization’s overall maintenance and lubricant budget. It’s no small feat.
One of the things that makes fleet management a lot harder for many organizations is heavy-duty engine oil compatibility. Not every engine oil is suitable for all vehicles, and fleet managers must consider this when ordering supplies and establishing lubrication and maintenance schedules. Many organizations try to reduce their lubricant inventory costs by finding heavy-duty engine oils that address the needs of most of their fleet. But finding one engine oil for a whole fleet is getting more difficult.
Heavy-duty engine oil compatibility has changed
One way fleet managers used to be able to meet their fleet lubricant needs was by choosing heavy-duty engine oils that were backward compatible, meaning they work with older engines. One popular choice was API specification commercial diesel engine oils. Engine oils that met this specification standard were designed to be backward compatible with new engine categories. For example, CK-4 oils can be used in CJ-4, CI-4, and CH-4 engine categories. The goal of the API specification was to meet the performance needs of previous oil categories while offering enhanced protection with each new category. But times are changing, and the API specifications are changing too. The newest API product category is now split into two levels:
- API CK-4 level that remains backward compatible up to a CJ-4 category.
- API FA-4 level that is only compatible with 2017 models and beyond.
Heavy-duty SASH level limits changed
The previous API CJ-4 category had no restrictions on sulfated ash, sulfur, or phosphorus, collectively known as SASH. So, these CJ-4 oils had higher zinc levels and could be manufactured from API group I or II base stocks. This factor helped make them backward compatible with older engines, making them very popular for fleets with a mix of older vehicles.
However, as emissions standards became more aggressive, DPF filters were required to remove even more emissions during usage. This change led to higher SASH levels in DPF filters. The more the filter was required to catch to reduce emissions, the more maintenance and filter changes were needed to keep DPF filters in good condition. Additives added to heavy-duty engine oils are the biggest culprits of SASH chemicals. These chemicals do not burn up with the rest of the engine oil when it enters the combustion chamber. Instead, they form into sulfates, which then poison the catalysts in the exhaust system, reducing its effectiveness and leading to more emissions.
CJ-4 oils meet new emissions standards
To meet the need for reduced emissions standards, a new CJ-4 oil category was created. This category limited SASH components in heavy-duty engine oil. Sulfur was limited to a maximum of 4,000 ppm, and phosphorus was limited to 1,200 ppm. This requirement meant that group base I stock could no longer be used to manufacture heavy-duty engine oils to meet this category, reducing the oil’s backward compatibility. This change reduced sulfate development and thereby reduced overall emissions.
How are phosphorous levels affected by these category changes?
Phosphorus in heavy-duty engine oils comes from the anti-wear agents added to the oil mixture. These agents help reduce corrosion and protect the engine from wear and tear, especially on vulnerable joints, pistons, and other mechanizations. But anti-wear additives also form the most SASH chemicals that clog up DPF filters. When these filters get too clogged, they do not work as effectively and allow more carbon emissions. It can also reduce the time between drain intervals, leading to more extensive DPF filter maintenance.
As the level of phosphorous and SASH chemicals allowed to be used in specific oil categories has changed, fleet managers’ lubricant strategy has shifted. There is no longer a one-size-fits-all oil that can meet the needs of every vehicle in the fleet. Instead, managers have to carefully assess the lubricant needs of each vehicle and incorporate them into their overall lubricant strategy. For example, some older vehicles may require more anti-wear protection but must still meet modern emissions standards. In that case, fleet managers must choose an ultra-low ash heavy-duty engine oil with significant anti-wear properties.
Universal heavy-duty engine oils are a thing of the past
While some heavy-duty engine oils are still marketed as universal, it’s important to double-check. Many of these so-called universal heavy-duty engine oils do not meet the phosphorus levels for C and S serve categories, which are meant to be between 600 – 800 ppm. This is the level that is acceptable for most engines starting in 2010. Engines older than 2010 can handle higher levels with a maximum of 1000 ppm.
So, what does this mean for fleet managers? They can’t rely on backward compatibility anymore for vehicles in their fleet older than 2010. Instead, they have to ensure they have lubricants in their shop that address the needs of older and newer vehicles. There is no longer a universal heavy-duty engine oil that can meet both needs.
Do lower phosphorous level heavy-duty engine oils provide the same level of protection?
One of the significant concerns with newer lower-level phosphorous level oils is the quality of lubrication they provide. Luckily, newer engines are designed to meet the demands of lower phosphorous levels. In an article from JobbersWorld on this topic, Steve Haffner of SGH Consulting was quoted: “The latest hardware is designed to operate on lower phosphorus oils, and you can take some comfort in knowing that there have not been reports of widespread issues with its use.” He continues with this sage advice: “Follow your owner’s manual and use the specified oil. Where possible, oil analysis can show if the engine is protected, and oil analysis is highly recommended to ensure the health of your vehicle, especially when drains are being extended. Nothing beats field-proven performance via oil analysis.”
Let us help you fine-tune your lubricant strategy
As you can see, fleet managers have a difficult job finding the right heavy-duty oils to meet the needs of all their vehicles. We’re here to help. As a Chevron Lubricants Supplier and a Valvoline Lubricants Supplier, we can help you fine-tune a lubricant strategy that considers all your vehicles’ needs, your operating budget, and ordering capabilities. With a large inventory to pick from and access to services like oil analysis, our customers can get the lubricant products they need to keep their fleets in great shape for years. Call today, and let’s discuss your organization’s lubrication strategy!