maintaining bobcat doosan fuel system best practices
Common Rail System
How To

How To Maintain Bobcat Doosan Fuel System Tier 4 Engine

When issues with your machine arise, you may automatically think there is something wrong with your engine when the issue often points to contaminated fuel from dirt, debris, water or air.

First, let’s get a better understanding of Tier 4 Engine technology. Tier 4 standards are mandated by the EPA for all heavy machinery and equipment such as forklifts, tractors, loaders, excavators and more. Tier 4 Engine introduced engine emission technology that includes a high pressure fuel injection system and exhaust after-treatment systems. Tier 4 engine standards first started making their way into the market from 2008 to 2014. Today’s diesel engines run more pristine than ever before, but this also makes them highly susceptible to issues from contaminants because the high pressure common rail, also known as the HPCR uses extremely precise components. Fuel pressure in these engines has also risen dramatically to as high as 30,000 psi. If there are contaminants in the fuel that are combined with high pressure, erosion will start to occur and cause a variety of problems. This is why clean fuel is critical for today's engines. Fuel can vary from one supplier to the next.

As engines have been going through radical design changes, the fuel industry has also been required to make some changes. They’re now required to remove all sulfur from diesel. The chemistry changes that come from ultra low sulfur diesel make it more challenging for fuel suppliers to consistently provide high performing fuels. Plus, refining and additive techniques vary from supplier to supplier. Current fuel standards just don’t address the cleanliness needed for HPCR standards.

If you use biodiesel, you should be mindful that it demands more periodic filter changes and it also creates more water-related challenges such as microbial growth. Biodiesel tends to degrade faster than petroleum-based fuels and there is also a higher chance that freeze up occurs when exposed to cold weather conditions. 

To select the best fuel supplier, make sure your fuel supplier uses water removing filters rated to 10 microns or less under fuel delivery lines.To avoid gelling/freeze up, utilize a blend of #1 and #2 diesel with a low cloud point temperature. Keep spare fuel filters around at all times for every HPCR engine and only use Bobcat approved fuel filters. More about replacing fuel filters here. 

To summarize, the three most common causes that can lead to fuel system issues are dirt and debris, water and condensation or air. Dirt or debris can contaminate your fuel and lead to costly issues. It’s important to know how dirt can get into your fuel. Water from humidity or rain can cause your fuel filter to clog and stop all fuel flow. Air from loose fuel lines or a faulty spray nozzle can enter and become trapped in the fuel injection system which can lead to a hard starting engine. To decrease your odds of running into these issues, follow the recommendations below. 

Some best practices to follow: 

  • Refill the fuel tank at the end of each work shift. We recommend keeping your tank to about 90 percent full to help reduce condensation such as humidity or oxygen exposure 
  • Source your fuel from a reliable supplier that uses water removing filters rated to 10 microns or less 
  • When refilling your tank, make sure the surrounding area is clean of any dirt, dust or debris that can fall in 
  • Never insert fuel prior to the fuel filter being installed 
  • Only use new diesel fuel 
  • Use clean fuel cans dedicated for diesel only and store them inside in a temperature controlled environment (70 degrees Fahrenheit or below). Read more about storing diesel fuel.
  • Use clean tools during repairs and maintenance
  • Drain the water trap daily to weekly. Read more about this process. 
  • You can use an additive such as a biocide or a stabilizer to prevent degradation. Read more about the best fuel additives.  
  • Make sure to follow all cold weather starting procedures
  • Use only Bobcat approved fuel additives 
  • Schedule in frequent maintenance and replace fuel filters around every 6 months or every 250 hours (whichever comes first). If using biodiesel, you should consider replacing it even more frequently. Keep spare fuel filters around.
  • Perform any maintenance indoors if possible, or avoid working maintenance work in windy conditions
  • Clean out your tank every so often, such as every few years at the very least 

A proactive fuel management strategy will help ensure reliable performance and prevent unexpected issues caused by fuel contaminants. In the long run, following these tips will help save you any headaches, time and money that comes from experiencing premature issues with your fuel system. 

If you do find that fuel system service is required and you need to purchase parts, we sell the complete fuel system kits for the Bobcat Doosan Engines D18, D24, D34 which includes the injectors, fuel injection pump, common rail, fuel lines, and o-rings. Search through our parts catalog today!