Not all trucks cruise along at highway speeds outfitted with aerodynamic technology. Some have much tougher duty – but not necessarily off-road trucking or oversize loads.
With average haul lengths are declining nationwide, drivers no longer travel at consistent, moderate speeds. Many hauls have shifted to in and around population centers, where traffic is heavier and the distances traveled are shorter.
Frequently, drivers must save fuel by shutting down their engine rather than idling, one of the toughest stresses on a diesel engine.
This is the new face of severe duty.
HOW THIS AFFECTS ENGINES
Diesel piston rings are designed to expand when the high pressure gases created during the power stroke impact them from the combustion chamber above. When an engine is under significant load or strain, the rings expand, holding in the high cylinder pressure – often well over 2,500 psi.
In this state, the rings do not scrape the oil effectively from the pistons, increasing oil consumption and deterioration. Lighter viscosity oil may amplify this problem, making it a bad fit for trucks with oil consumption issues.
Increased fuel consumption – common in stop-and-go driving – also accompanies oil deterioration, as both the heat and the amount of the blowby escaping the piston rings and entering the crankcase increase.
In our research, we’ve found it is critical to properly maintain engine temperature. An 18 degree F increase in engine temperature can cut oil life in half.
COOLANT MAINTENANCE
One way to maintain engines facing severe duty is by developing coolant maintenance programs that address the challenges your fleet is facing. While many fleets have coolant programs, many are insufficient for severe duty applications.
In our experience, developing a proper coolant maintenance program for a fleet as small as six trucks can take one to two years. These programs should include steps like:
- Maintaining the cooling system fluid level.
- Ensuring that the coolant is kept in top condition with ideal chemistry to prevent corrosion and deposits.
- Strategically deploying Extended Life Coolants (ELC). These eliminate the thin layer of Supplemental Coolant Additives on cooled metal.
- Checking freeze points regularly.
- Properly training those maintaining cooling systems.
Good coolant management will result in fewer cooling system failures and improved engine performance.
OIL ANALYSIS
Changing the way you use a truck will immediately affect the way it operates. Every use situation is different, and working with experts is the best way to identify the proper maintenance programs.
Different engine patterns will affect oil consumption and will cause changes to your oil with major ramifications for your fleet’s engines down the line.
OEMs and oil providers offer the best insights into how to properly maintain your fleet and will work with you to implement upgrades and changes. Oil analysis will review factors like oil formulations, drain intervals, Total Acid Numbers (TAN) and Total Base Numbers (TBN) to optimize oil performance and maximize engine life.
Following an analysis, the experts can provide you with detailed instructions on how to implement maintenance changes. It’s an easy solution – but it’s one that many fleet maintenance professionals don’t take advantage of at this time. While many analysis packages do not offer TAN numbers, this number is growing in importance and we recommend having a discussion with your provider.
KEEP CURRENT
Changing driving habits are on the radar of every forward-thinking company in the trucking industry. While the advice offered here is intended to help maintenance professionals keep their fleets running efficiently, realize that companies are continuing to develop research and new tools to protect trucks, and new solutions are being developed every day.
Keep up with the latest development to make sure your fleet operates at its best all the time.
Jim Gambill is the commercial and industrial brands manager for Chevron Products Company, which manufactures, markets and distributes petroleum products. It is a division of Chevron U.S.A. (www.chevron.com/countries/usa).
