Understanding and Solving the Bobcat Making Oil Issue

[MikePhua]

The issue of a Bobcat machine "making oil" is a common yet concerning problem in the heavy equipment world. When this happens, it means that the machine’s engine is somehow contaminating the oil with diesel fuel or other fluids. This can lead to severe damage to the engine and other critical components, making it essential for operators to address the issue as quickly as possible. In this article, we’ll explore the causes of this problem, common solutions, and how operators can prevent such issues from escalating.
What Does "Making Oil" Mean?
In simple terms, when a Bobcat (or any other diesel engine machine) is said to be "making oil," it usually means that the engine is allowing diesel fuel to enter the oil system. This causes the oil to become diluted with fuel, which can dramatically reduce the oil’s lubricating properties. Over time, this can lead to increased wear, engine damage, and even complete failure if not addressed promptly.
In addition to diesel fuel, coolant can sometimes mix with the oil, leading to a similar issue. While coolant mixing with oil is often a result of a head gasket failure or a cracked engine block, fuel dilution is usually related to the engine’s fuel injection system, particularly with older or worn-out components.
Common Causes of Fuel Contamination in Bobcat Machines
Several factors can contribute to fuel contamination in Bobcat machines. Here are some of the most common causes:

1. Worn Fuel Injectors:
   One of the most common reasons for fuel dilution in the oil is worn or malfunctioning fuel injectors. Fuel injectors are responsible for atomizing the fuel into a fine mist that mixes with air in the combustion chamber. If the injectors are worn out or malfunctioning, they may deliver too much fuel, which doesn’t burn efficiently. This excess fuel then escapes into the crankcase, where it mixes with the engine oil.
   Solution: If the injectors are the problem, replacing them with new or refurbished ones is typically the solution. Additionally, cleaning the fuel system to remove any debris and ensure proper fuel atomization can help prevent further issues.
   
2. Faulty Fuel Pressure Regulator:
   The fuel pressure regulator ensures that the fuel system maintains the correct pressure for optimal combustion. If the regulator fails, it can cause excessive fuel delivery, leading to an increased likelihood of fuel mixing with the oil.
   Solution: Replacing the faulty fuel pressure regulator and performing a thorough inspection of the fuel lines and system is necessary to resolve the issue.
   
3. Excessive Idle Time:
   Diesel engines are designed to operate efficiently when they are working under load. Prolonged idling without proper engine load can cause incomplete combustion, which leads to unburned fuel making its way into the oil system.
   Solution: Reducing idle time and ensuring that the engine runs under load for proper combustion is essential. Regular operation at higher RPMs will help burn off excess fuel and prevent it from contaminating the oil.
   
4. Blown Head Gasket or Cracked Cylinder Head:
   Another potential cause of oil contamination is a blown head gasket or cracked cylinder head, which allows coolant to leak into the oil. This is often accompanied by white smoke from the exhaust and a noticeable drop in engine performance.
   Solution: Repairing or replacing the head gasket or cylinder head is the only solution in this case. It is vital to address this issue quickly to avoid catastrophic engine damage.
   
5. Short Operating Cycles:
   Short work cycles with frequent stops and starts can also lead to incomplete combustion and the accumulation of unburned fuel in the engine oil. This is often seen in machines that are used intermittently or for short bursts of time.
   Solution: Operating the machine for longer periods at a steady pace and ensuring that the engine reaches optimal operating temperature can prevent the issue of unburned fuel entering the oil.
   

Signs That Your Bobcat is Making Oil
There are several key signs that indicate your Bobcat may be making oil:

1. Oil Level Increases:
   If you notice that the oil level is increasing without adding oil, it is a clear sign that fuel is mixing with the oil. Diesel fuel has a much lower viscosity than oil, so it can lead to a rise in the oil level as it dilutes the existing oil.
   
2. Fuel Smell in Oil:
   If you detect a distinct fuel smell when checking the oil, it indicates that diesel fuel has mixed with the engine oil. This is one of the most obvious signs of fuel contamination.
   
3. Excessive Smoke from the Exhaust:
   If the engine is burning excess fuel, you may notice white or black smoke coming from the exhaust. This can happen if the engine is not burning the fuel completely due to malfunctioning injectors or poor combustion.
   
4. Engine Overheating:
   Fuel-contaminated oil loses its ability to lubricate the engine effectively, leading to increased friction and heat buildup. If you notice that the engine is running hotter than usual, it could be due to fuel dilution in the oil.
   
5. Poor Engine Performance:
   When fuel mixes with oil, the engine’s performance can degrade. You may experience reduced power, misfires, or rough idling. This is often accompanied by increased exhaust smoke and a decrease in overall engine responsiveness.
   

How to Address the Bobcat Making Oil Problem
Once you’ve identified that your Bobcat is making oil, it’s important to act quickly to prevent severe damage. Here’s a step-by-step guide to addressing the issue:

1. Change the Oil Immediately:
   If fuel contamination is detected, the first step is to drain the contaminated oil and replace it with fresh, clean oil. Make sure to use the appropriate oil grade and follow the manufacturer’s specifications for your Bobcat model.
   
2. Inspect the Fuel System:
   Examine the fuel injectors, fuel pressure regulator, and fuel lines for any signs of wear or damage. Replace or clean faulty components to prevent further contamination.
   
3. Check for Engine Damage:
   If you suspect a blown head gasket or cracked cylinder head, perform a compression test or a cooling system pressure test to diagnose the problem. If necessary, repair or replace the damaged components.
   
4. Perform Regular Maintenance:
   Regularly service your Bobcat by changing the oil, inspecting the fuel system, and monitoring the machine’s performance. Following a strict maintenance schedule will help prevent the issue of fuel contamination in the future.
   

Preventative Tips to Avoid Making Oil

1. Limit Idle Time:
   Avoid excessive idling, as this can lead to incomplete combustion. Try to keep the engine running under load to burn fuel efficiently.
   
2. Operate at Optimal Temperatures:
   Ensure that the engine operates at the proper temperature for extended periods, which helps in the complete combustion of fuel.
   
3. Regular Fuel System Inspections:
   Inspect and clean the fuel injectors, fuel filter, and pressure regulator regularly to ensure they are working efficiently and not contributing to fuel dilution in the oil.
   
4. Monitor Oil Levels and Quality:
   Frequently check the oil levels and inspect the oil’s condition. If you notice any abnormalities, such as an increase in oil level or the presence of a fuel smell, address the issue promptly.
   

Real-World Example: Bobcat 863 with Fuel Contamination
A landscaping company in California experienced issues with their Bobcat 863 skid steer, which began showing signs of “making oil.” After noticing a rise in the oil level and a strong diesel smell from the oil, they immediately changed the oil and noticed that the engine was running smoother. Upon further inspection, they discovered that a fuel injector was leaking, causing excess fuel to enter the engine oil system. After replacing the faulty injector and cleaning the fuel system, the issue was resolved, and the skid steer was back to work with no further problems.
Conclusion: Keep Your Bobcat Running Smoothly
The issue of a Bobcat "making oil" can be alarming, but with quick detection and timely repairs, it can be addressed without causing long-term damage to the machine. Regular maintenance, proper operation, and routine inspections of the fuel system can prevent fuel contamination and keep your Bobcat running at peak performance for years to come. By being proactive and attentive to your machine's needs, you can avoid costly repairs and ensure your equipment performs efficiently and reliably.