7 Little Changes That’ll Make a Big Difference With Your Diesel

Warm it up

Diesel engines clatter when they are cold. This is because diesel engines rely on the heat generated by compressing air in the cylinders in the engine for the diesel to ignite, with a cold block and cold air, combustion is not very efficient. When you start a diesel engine for the first time of the day, let it idle for a few minutes. This gives the engine ample time to circulate oil efficiently and gives the cylinders enough time to build up heat for efficient combustion.

Keep it cool

Excessive heat is a killer of diesel engines, in order to prevent costly problems, it is important to monitor EGTs (exhaust gas temperatures) with a pyrometer, avoid EGT temperatures exceeding 1250 degrees Fahrenheit for any period of time, let off the throttle or bring up the RPMs by kicking down to a lower gear to avoid lugging the engine.

Turbocharger Care 

The turbocharger in modern common-rail diesel engines is one of the most critical components in the engine. Turbocharger compressor wheels can exceed 100,000 RPM, compressing air to high pressure and forcing it into the engine. Because the turbocharger spins at such high rpm, it is important to make sure it is adequately lubricated.

Before you turn the engine off, it is important to let the engine idle, enabling the turbo to cool down, to avoid damage to the bearings and plugging of the passages by burnt oil (coking).  Running at full speed and full load then immediately shutting down (heat soak) can be extremely hard on a turbo. Though, in some turbochargers, water-cooling of the turbocharger’s center housing has essentially eliminated the need for extended idling periods.

Breathe clean air

Diesel engines rely heavily on high volumes of clean air for efficient combustion. This means that you need to keep your air clean at all times. Even small quantities of dust getting past the air filter can result in quite a bit of loss in performance, damage your turbocharger (dusting), rings and pistons. Replace or clean the filter element as recommended by the manufacturer, depending on service duty and conditions, ensure there are no post filter leaks in your air intake hoses.

Mind that oil

Engine oils have to work much harder in diesel engines, HEUI (Hydraulically Actuated Electronic Unit Injector) injectors are controlled by and utilize highly pressurized engine lubrication oil to drive plungers pressurizing fuel for injection. Therefore it is imperative that your diesel engine is getting the cleanest and best quality oil possible. Follow the manufacturer’s recommended oil change routine. Use only oils recommended for diesel engines.

Keep the injectors clean

Diesel injectors in modern common-rail diesel engines are quite sophisticated. They are electronically actuated and inject precise amounts of diesel fuel at greater than 20,000 PSI directly in the cylinder, sometimes multiple times per combustion cycle, in fractions of a second. Even the slightest bit of soot or sludge can clog up the injectors, resulting in loss of power and excessive smoke from the exhaust.

Probably the biggest result of injector failure is due to the injectors having excess return flow or back leakage. This is due to worn parts which allow excessive fuel to go through the diesel injector and to return back to the tank or fuel system. This causes a drop in rail pressure which results in hard starting or not starting at all. Use a branded diesel injector cleaner additive to keep the injectors clean and well lubricated. 

Do not let the fuel tank run dry

If you are unfortunate enough to drain the last drop of diesel from your tank, it will be necessary to bleed any air that has entered the fuel system. When you refuel, you may need to “prime” the fuel bowl by cycling the key without starting the engine a few times, in order to get the diesel to flow smoothly to the engine again.

Looking for more general info and tips for diesel engines? Check out our guides including 5 Diesel Engine Myths Busted and the truth about rolling coal.