The hidden impact of engine idling

Vehicles in the waste sector operate under some of the toughest conditions, with fleets regularly idling for significant periods of time. Additionally, fleets are exposed to a wide variety of harsh operating conditions that are known to increase fuel consumption, risk heightened engine wear and consequently lead to unplanned maintenance and downtime.

To protect against wear, boost reliability, and improve fuel economy, waste fleets must be aware of and address the hidden impact that regular and prolonged idling can have.

The impact of idling

Waste fleet vehicles spend a lot of time at idle. Every time the vehicle stops for a pickup it is idling. Komatsu estimates that an average vehicle will spend 40 percent of its time idling when in use. And, given the environment that waste fleets operate in and their stop/start nature, the impact is higher for this industry.

Just a single hour of idle time can cost the equivalent of approximately 40 kilometres of driving, in terms of fuel and wear.

The detrimental impact on engine wear increases the likelihood that oil temperatures will drop below 100oC due to reduced engine loading. A drop in temperature can alter the combustion process and is often overlooked as an issue to address.

When the process is altered, water
can accumulate, leading to an increased risk of acid formation and fuel dilution as well as reduced oil viscosity. These factors can accelerate the rate of engine wear and shorten oil drain intervals.

Furthermore, when increased fuel dilution occurs, the volatility of the oil rises, which can lead to a heightened amount of soot finding its way to the Diesel Particulate Filter (DPF). Significant fuel economy is then lost due to the increased regeneration cycles needed to clean the DPF.

Not only does idling affect engine wear but it can also increase upfront costs. It is estimated that as much as four litres of fuel is used each hour a vehicle is left idling. Reducing engine idling presents benefits for environmental and financial gains, whether increasing fuel efficiencies or reducing emissions.

Choosing the right oil

Using a quality lubricant can improve an engine’s pumping and rotational efficiencies while minimizing metal-to-metal contact between components. Quality engine oils also protect the vital internal hardware of the vehicle, while enhancing engine performance and fuel economy. The choice of lubricant can have a considerable impact on the engine.

For those in heavy-duty industries such as waste fleets, API CK-4 oils are now widely adopted. These oils protect against oxidation and aeration and offer increased shear stability. Heavy-duty vehicles can benefit enormously from improved aeration control as they can take on more air than others in their engine oil, especially at the bearings, which require an oil film to ensure protection.

To help reduce the work rate of the engine, a lower viscosity oil is recommended. This is particularly beneficial for fleets operating during the colder winter months as the lower viscosity oil enables easier cold starts and provides added protection against frequent stop and starts.

In these colder conditions, a high viscosity could mean that the oil resists easy movement and delays lubrication, ultimately hindering the protection of the engine and increasing wear on parts. Industry standard tests such as ‘Cold Crank Viscosity’ (CCS) and ‘Low Temperature Pumpability’ (MRV) should be used to ensure that the chosen oil will lubricate critical components even in the coldest of operating conditions.

Monitoring impact

To monitor the impact that engine idling has on waste fleet vehicles, operators should incorporate used oil analysis into their maintenance routine. Used oil analysis can highlight maintenance issues caused by extensive idling before they become too serious or expensive to repair. Waste fleet operators can then adjust maintenance schedules in line with the findings of the report to prevent costly unplanned downtime.

Oil analysis and robust maintenance programs are key components of tackling the impact of idling in harsh conditions. Waste fleet operators should take time when selecting their engine oil as a superior lubricant can offer vital protection for engine components, shielding them from the hidden impacts of engine idling.

The nature of their role means that waste fleets are likely to always be subject to longer idling times and tough operating conditions. However, there are proactive measures that can be taken to reduce the effects of that idling on fuel efficiencies and engine wear, and address risks to reliability. Regular oil analysis, a proactive maintenance program and, above all, a quality lubricant can have a dramatically positive effect, especially on the company’s bottom line.


Darryl Purificati is OEM technical liaison, Petro-Canada Lubricants.