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Tips for Maintaining Tier 4 FINAL aerial work platforms

Tips for Maintaining Tier 4 FINAL aerial work platforms

After decades of preparation, aerials with Tier 4 Final engines are beginning to find their way into rental fleets. The Environmental Protection Agency (EPA) outlined a tiered series of emissions regulations for off-road engines in equipment in the mid-1990s. Tier 4 Final (T4F) is the culmination of the EPA’s mandate, and all new Genie diesel-powered aerial work platforms (AWPs) and telehandlers are in compliance.

T4F engines significantly reduce carbon emissions, increase fuel efficiency and allow for longer service intervals. And while T4F models have several benefits when compared to older models, Galen Wickstrom, Genie National Accounts Manager, Terex AWP, says that there are several new maintenance-related tips that owners should observe, as well as encourage customers to do, to get the best performance and longest life out of this equipment’s engines. Electronic diesel engines

To start, it’s important to understand how T4F engines differ from those found in older models. 

Engine manufacturers have switched from mechanical engines to electronically controlled engines, which means that the fuel injection and timing that was once controlled by gears, a camshaft and rockers are now run by an engine control module (ECM). The ECM also regulates the engine’s aftertreatment system to control soot and NOx gas, nitrogen and oxygen compounds released into the environment. 

Gone are the days of simple muffled exhaust. Today’s diesel engines use exhaust gas recirculation (EGR) circuits and/or selective catalytic reduction (SCR) systems to reduce emissions by 50 to 96 percent. The new technology requires operators and mechanics to think about their machines a little differently than they did before.

Run the engine hot

Unlike the older engines, T4F engines are designed to run hot all the time. The heat ensures that the engine produces the right amount of power, makes sure the piston rings seat properly and helps the aftertreatment system remove pollutants. 

Because these engines do run hot, they can burn some oil, so operators need to make sure to check oil levels more often and add oil when needed.

Ultra-low-sulphur diesel

The quality of the fuel and oil used in T4F engines is critical. These new engines are designed to run on ultra-low-sulphur diesel and low-ash oil, widely available through fuel and lubricant suppliers. Older mixes of off-road diesel don’t burn clean enough and cause issues with these engines’ injection and fuel management systems.

The biggest enemy to T4F engines is water. New high-pressure fuel systems deliver fuel at almost a molecular level. The fuel pump and turbocharger may depend on the fuel for lubrication, and when water is introduced into the system, the results can be costly. So, it’s important to keep fuel clean throughout the fueling process. Whenever possible, avoid the use of gas cans (jerry cans) because they can easily be compromised by water and dirt. In addition, keep fuel supply tanks clean.

If there is ever an engine malfunction that you suspect is related to fuel, take fuel samples immediately. A fuel sample may be able to indicate the source of your issue, and the longer the wait, the more likely the fuel sample is to be compromised.

Fuel water separator

Any Genie product with a 49-hp diesel engine and above will be equipped with a fuel water separator. It is important for operators to pay attention to the warning indicator light that illuminates when the separator is 70 percent full. Have them drain the separator on a daily basis. If the separator is not emptied regularly, water can begin to bypass the separator and penetrate the fuel system.

Exhaust system

The exhaust system on T4F engines is more robust and heavier than mufflers and catalytic converters on older products, so clamps and mounting brackets should be visibly inspected on a regular basis. Vibration can loosen up clamps over time; if that goes unnoticed, it could lead to an expensive repair. Tell operators that if they hear something rattling, take a minute and find out what it is. An ounce of prevention is worth a pound cure.


Depending on the size and make of the T4F engine, aerials may be equipped with a diesel particular filter (DPF), which will occasionally have to perform a regeneration process to burn off particle matter trapped in the DPF. 

For some machines, enough heat is generated to clear the DPF through passive regeneration; this does not impact machine operation. Low-duty-cycle machines require active regeneration, requiring the operator to park a machine while it goes through a full manual regeneration. 

Whether the aerials perform passive or active regeneration, it’s important to complete the process. Failure to do so will result in machine derating or shutting down to protect the system. If that happens, a qualified service professional will have to inspect the machine and clear the error code.

Diesel emissions fluid

If an aerial is equipped with a diesel emissions fluid (DEF) tank, make sure operators are checking the levels on a daily basis. DEF is a colourless, nonhazardous chemical that has been incorporated in most 75-hp engines and higher to help meet Tier 4 emission standards. Failure to refill DEF will lead to the machine derating or shutting down… it’s like running a machine out of fuel.

Warning indicators

Pay attention to any dashboard or operator panel warning lights and take immediate action. T4F engines are finely tuned, and these indicators will only illuminate in the event of an issue. Ignoring them can lead to costly repairs and downtime.

Service intervals

Become familiarized with recommended service intervals outlined in the aerial’s owners’ manual. Most T4F models have extended intervals when compared to older machines. However, it’s important to perform routine maintenance as outlined, using either OEM filters or a close cross match. Do not push filter life; these engines do not tolerate stretching service intervals. This may present a challenge on long-term rentals and may require owners to perform maintenance in the field.

Also, when questions come up, call your Genie service technician.

Certified training
The EPA put the burden of compliance on the manufacturer, which means we, Genie, are responsible for ensuring our aerial equipment continues to meet emission standards. This is why it’s imperative to only have certified mechanics working on these motors. Engine manufacturers do offer courses for rental service technicians to become certified, something rental owners may want to consider as the fleet of T4F units continue to expand. With proper training, engine manufacturers will give owners more access to equipment and permission to reading and resetting default codes, saving time and money.

The future of diesel engines is here, and following these tips will help get the longest life from any equipment investment. 

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