Don't idle on idling! Understanding how engine hours are calculated could make a huge difference in your fleet financials. - Mike Antich

Don't idle on idling! Understanding how engine hours are calculated could make a huge difference in your fleet financials.

Mike Antich

One ongoing industry trend is more stringent enforcement of manufacturer-recommended preventive maintenance (PM) services required for warranty coverage eligibility. Increasingly stringent warranty enforcement underscores the importance of PM compliance and documentation of services performed.  

Here’s the consequence: fleets must adhere to the OEM’s PM recommendations and diligently follow these guidelines. Specifically, OEMs want additional documentation to support warranty claims to ensure a unit was maintained properly before the failure occurred. During the warranty claims process, a fleet’s adherence to PM schedules are closely scrutinized, with the focus being PM variability. A complete maintenance history is critical for warranty recovery efforts that documents the manufacturer’s recommended PM schedule has been followed. 

PM on Engine Hours for High-Idle Units

Excessive engine idling doesn’t just consume fuel; it also creates engine hours. Depending upon the OEM, engine hours are used to determine when the powertrain warranty expires. Engine hours refers to the number of hours an engine has been running since it was first manufactured, regardless of whether or not the vehicle is moving. Another way of viewing an engine hour is not only as a measure of time, but also as 100,000 crankshaft revolutions. Excessive engine hour usage creates wear-and-tear on the engine requiring more frequent PM intervals. 

Certain fleet applications require a vehicle to idle for long periods to operate auxiliary equipment using a power take-off, which doesn’t create odometer mileage since the vehicle is stationary.
One hour of idling is equal to 25 to 30 miles of driving. High engine hours in low-mileage vehicles can create potential issues that void warranty compliance. Some fleets don’t realize this and are surprised when they are denied coverage, thinking the vehicle is within the warranty mileage parameters or has followed the manufacturer’s recommended maintenance schedule.

Excessive engine hour usage creates wear-and-tear on the engine, decreasing engine life, requiring more frequent PM intervals to stay in warranty compliance. In addition to accelerating warranty expiration, excessive engine hours can also void a warranty, especially if you only follow mileage parameters for oil drain intervals and filter (oil, fuel, and air) replacements. To illustrate this point, one dealer cited a municipal parks and recreational vehicle with only 77,000 miles on the odometer which suffered an engine failure within the mileage warranty parameters, but it was denied coverage due to excessive engine hours. The reason given was that the motor had extremely high engine hours and the inside of the motor was completely sludged despite the fact the motor oil was changed consistently every 5,000 miles. The vehicle idled often, however,  and once the actual idle time was estimated, it was determined the vehicle should have had three PMs done during the 5,000-mile interval instead of only one. After converting the engine hours to miles, the “77,000-mile engine” for the parks and recreation truck actually had around 270,000 miles. As a consequence, the warranty work was denied because the oil drain interval was inadequate to the actual engine usage.

Negligence with Diesel Emission Systems

Another potential issue with warranty compliance involves the diesel emissions system, such as diesel particulate filters (DPFs), selective catalytic reduction (SCR) systems, and diesel exhaust fluid (DEF). Full regeneration (burning off of soot) of the DPF in urban applications is difficult when there may be as many as 30 to 40 stops per day. If a driver doesn’t accelerate a truck to highway speed long enough to allow for a full regeneration cycle, eventually, the DPF filter will clog. Any system that directly interfaces with the engine (such as fuel, cooling, and exhaust) is strongly impacted by high engine hours. For instance, a truck in a high-idling fleet application is less likely to generate temperatures high enough to perform optimal regenerations for the diesel oxidation catalyst.

During long periods of idling, the operating temperature is lower than a typical duty cycle, necessitating more manual regeneration. The increased costs related to new emissions technologies have leveled off as fleets and drivers have become more familiar with the trucks. Still, there is a constant stream of new drivers entering the workforce who may not be familiar with diesel emissions requirements.

Nowadays drivers are increasingly more responsible for proper maintenance protocols and it is important fully understand the operations of the trucks they’re driving. When it comes to filling the DEF tank, even today some drivers put the wrong product in the wrong tank, creating a potential warranty issue that requires a fleet to back-clean the system. To avoid needless warranty issues, it is critical to ensure proper driver compliance with maintenance responsibilities when operating a unit. 

Document, Document, Document

The bottom line is that truck fleet managers need to be diligent in tracking and documenting PM work to ensure there is no PM variability, to educate drivers on vehicle operations to avoid dumb mistakes, and to keep track of not only miles, but also engine hours. To increase the probability of receiving post-warranty goodwill assistance for issues that occur just outside the warranty coverage period, OEMs consider customer loyalty and documentation of a vehicle’s complete maintenance history.

Let me know what you think at [email protected].

About the author
Mike Antich

Mike Antich

Former Editor and Associate Publisher

Mike Antich covered fleet management and remarketing for more than 20 years and was inducted into the Fleet Hall of Fame in 2010 and the Global Fleet of Hal in 2022. He also won the Industry Icon Award, presented jointly by the IARA and NAAA industry associations.

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