Understanding Total Base Number in today’s HD engine oils

Understanding Total Base Number in today’s HD engine oils

Sponsored by Phillips 66 Lubricants

Total Base Number (TBN) has been a key indicator of remaining useful oil life in heavy duty engine oils. While acid neutralization is still an important function of engine oil, changes in engine design and the move to Ultra Low Sulfur Diesel (ULSD) fuels have decreased the amount of acids produced in the engine and also resulted in generally weaker acids being produced.

The test methods

ASTM D2896 is the test method most commonly used to measure TBN on new oils. Use of a very strong acid identifies both “hard” and “soft” TBN, giving the total alkalinity reserve of the sample. The value obtained from this test is the number reported on most technical data sheets.

ASTM D4739 is the test favored by oil analysis labs on used oil samples. Using a weaker acid, it only identifies alkalinity from metallic elements like calcium, magnesium, and zinc. These metals are often doing double-duty in the oil (calcium provides detergency and acid neutralization; zinc in the popular antiwear additive ZDDP also contributes to anti-oxidation). This test does not identify newer ashless (i.e. non-metallic) additives, and reported values will be lower versus ASTM D2896.

The spread in values between the two test methods is now three times bigger than it was during CI-4+ and double that of CJ-4.

Engine OEMs have noticed

A quick and easy rule of thumb for most oil analysis laboratories and many fleet maintenance managers is to drain the oil when the TBN reaches 1/3 of its starting value or 3.0 mg KOH/g, whichever comes first. Detroit recently released its 2018 Service Bulletin (DDC-SVC-BRO-0001) in which it has removed TBN limits entirely from the used-oil analysis parameters. Discussions with other key engine builders has revealed that they have noticed that used-oil TBN values are often very low – sometimes below 1.0 mg KOH/g – yet without any additional indications of adverse oil condition. We expect other engine builders in time to follow Detroit’s lead and either update or eliminate their TBN guidelines.

What to monitor if not TBN?

When looking at used oil analysis reports, the full range of available data should always be considered. A better practice is for Oxidation/Nitration values above 25 units to get your attention, with a condemning limit between 35–40. This measure also should be paired with the viscosity trend to determine when oxidation is about to accelerate.

Relevant or relic?
Because additive chemistry has shifted, standard used-oil TBN testing protocol simply doesn’t provide the same level of insight that it once did. In the last 20 years much has changed – diesel fuel has dropped from 500 parts per million sulfur to a max of 15 ppm, fewer and weaker acids are found in used oil, engine designs have evolved, and oil chemistry has improved dramatically. While TBN was once an easy and effective way to predict remaining oil life, it no longer bears that relevance.

This article was sponsored by Phillips 66 Lubricants. For more information, please visit our website at www.phillips66lubricants.com

You May Also Like

Protecting both sides of the trailer floor is the best way to combat corrosion and maximize service life and it’s one company’s mission to solve this industry problem

Trailer manufacturers are always looking for ways to combat corrosion by using alternative materials and coatings. Rockland Flooring produces a combination of products that will preserve the wood, improve performance, and extend service life. According to Chris Wolford, Chief Sales Officer for Rockland Flooring, “The entire underside of a trailer’s floor is subject to many

Trailer manufacturers are always looking for ways to combat corrosion by using alternative materials and coatings. Rockland Flooring produces a combination of products that will preserve the wood, improve performance, and extend service life.

According to Chris Wolford, Chief Sales Officer for Rockland Flooring, “The entire underside of a trailer’s floor is subject to many extremes, including water, so it’s a great place for fleets to invest in additional moisture protection”. Chris goes on to say, “most undercoating will wear over time and require routine maintenance, so protecting the floor from the start is imperative to achieving maximum performance and floor life.  Our Defender TM line of composite floors and Grip Guard products were designed with this in mind.”

Hutchens Industries says Genuine Hutch spring hangers are dimensionally correct for geometry and fit

All Genuine Hutch parts have a 5-year warranty, supporting Hutchens Industries’ goal to make products that work for years, not 30 days.

Hutchens-Industries-logo
How Advanced Trailer Telematics Makes the Road a Safer Place

Keeping the road safe is paramount to any transportation business. Of course it saves lives, which comes before anything else. Beyond that, though, safer roads reduce unscheduled downtime, unexpected roadside events, and slow downs that can throw scheduling into a whirlwind and disrupt weeks worth of logistical planning. Advanced trailer telematics offer increasingly better insights

Hutchens Industries says Genuine Hutch torque arms are built to last

All Genuine Hutch parts have a 5-year warranty, supporting Hutchens Industries’ goal to make products that work for years, not 30 days.

Hutchens-Industries-logo
ACES® and PIES™ Compliance Tips for the Heavy-Duty Aftermarket

What you Need to Know about ACES® and PIES™ ACES® and PIES™, maintained by the Auto Care® Association, is your roadmap to navigating the complexity of automotive aftermarket parts and product data. These industry standards ensure accurate fitment and product information for smoother operations, improved customer experience, and enhanced supply chain efficiency. By consistently utilizing

Other Posts

Improve KPIs for your shop and fleet today.

Key Performance Indicators (KPIs) are goals or targets that organizations use to measure progress against their strategic objectives. Tracking KPIs is critical in industries with tight margins – such as commercial transportation – as they help provide managers with insights into performance and efficiency. Businesses can optimize operations and increase profitability by tracking and analyzing

Mitchell 1 TruckSeries commercial truck repair software

Put powerful, easy to understand CV diagnostics at your fingertips with TruckSeries by Mitchell 1.

Mitchell-1-Truck-Series-Sponsored-Content-600
From hands-on training to video-based learning: Keeping truck technicians trained

Hendrickson’s service philosophy on how to teach the next generation of technicians.

The Future of Trailer Telematics: Going Beyond Track & Trace

The Benefits of Integrating Trailer Telematics with Fleet Management Systems