Fuel Tank Configuration and Maintenance on the International TD15C Dozer

[MikePhua]

The TD15C and Its Mechanical Heritage
The International TD15C crawler dozer was produced by Dresser Industries in the late 1970s and early 1980s, continuing the legacy of the TD series originally developed by International Harvester. With an operating weight of approximately 33,000 pounds and powered by a DT-466 turbocharged diesel engine, the TD15C was designed for mid-range earthmoving tasks in construction, forestry, and mining. Its robust undercarriage, torque converter transmission, and hydraulic blade control made it a favorite among operators who valued mechanical simplicity and field serviceability.
One of the more overlooked components in older dozers is the fuel tank system. On the TD15C, the tank is integrated into the rear frame structure, serving both as a reservoir and a counterweight. Understanding its layout, capacity, and service points is essential for reliable operation—especially in remote or high-demand environments.
Terminology Notes

• Fuel Pickup Tube: A pipe inside the tank that draws fuel toward the engine via suction.
  
• Return Line: A hose that routes unused fuel back into the tank after passing through the injection system.
  
• Sediment Bowl: A small container that collects debris and water from the fuel before it reaches the filters.
  
• Vent Line: A tube that allows air to escape or enter the tank to prevent vacuum or pressure buildup.
  

Fuel Tank Layout and Capacity
The TD15C’s fuel tank is mounted at the rear of the machine, beneath the operator platform and behind the engine compartment. It typically holds between 70 and 80 gallons of diesel, depending on configuration and optional auxiliary tanks. The tank is fabricated from heavy-gauge steel and welded into the frame, making removal difficult but not impossible.
Key features include:

• Top-mounted fill neck with locking cap
  
• Internal baffles to reduce sloshing during travel
  
• Bottom drain plug for sediment removal
  
• Dual fuel lines: one for supply, one for return
  
• External sight gauge or dipstick for level monitoring
  

A forestry crew in British Columbia modified their TD15C with a secondary tank mounted above the main reservoir, connected via gravity feed. This extended their operating range by 40% during remote logging operations.
Common Issues and Diagnostic Tips
Fuel tank problems on the TD15C often manifest as:

• Engine stalling or hesitation under load
  
• Difficulty starting after refueling
  
• Fuel leaks near fittings or seams
  
• Contaminated fuel causing injector or pump damage
  

Typical causes include:

• Clogged Pickup Tube
  • Debris or sludge blocks suction flow
    
  • Solution: Remove and clean tube, flush tank interior
    
• Cracked Return Line
  • Fuel leaks or air ingress disrupt pressure balance
    
  • Solution: Replace hose and clamps, inspect routing
    
• Vent Blockage
  • Tank vacuum prevents fuel flow
    
  • Solution: Clean vent line and check for mud or insect nests
    
• Rust or Sediment Accumulation
  

• Internal corrosion contaminates fuel system
  
• Solution: Drain tank, inspect with borescope, apply rust inhibitor
  

A technician in Texas resolved a recurring stall issue by discovering a collapsed pickup hose inside the tank. Replacing it with a reinforced line restored full fuel delivery and eliminated the problem.
Preventive Maintenance and Upgrade Options
To keep the TD15C’s fuel system in top shape:

• Drain sediment from the tank every 500 hours
  
• Replace fuel filters every 250 hours or sooner in dusty environments
  
• Inspect fuel lines quarterly for cracks or abrasion
  
• Use biocide additives to prevent microbial growth in stored diesel
  
• Install a water separator upstream of the injection pump
  

Some owners retrofit their TD15Cs with quick-access inspection ports or external fuel polishing systems. A mining crew in Argentina added a magnetic fuel conditioner to reduce injector wear and reported smoother engine performance over time.
Operator Anecdotes and Field Wisdom
A retired operator in Montana recalled his TD15C sputtering during uphill pushes. After checking the basics, he found the fuel pickup tube had rotated inside the tank, drawing air during tilt. Repositioning the tube and securing it with a bracket solved the issue.
In Alberta, a contractor added a transparent sight tube to the side of his tank, allowing visual fuel checks without opening the cap. This simple upgrade reduced refueling errors and improved shift planning.
Recommendations for Technicians and Fleet Managers
When servicing the TD15C fuel system:

• Always depressurize the lines before disconnecting
  
• Use clean containers when draining or transferring fuel
  
• Document hose replacements and tank cleanings in service logs
  
• Train operators to recognize early signs of fuel starvation
  
• Coordinate with parts suppliers for compatible fittings and hoses
  

A fleet manager in Georgia created a fuel system checklist for his TD-series machines, including tank inspection, line routing, and filter condition. This reduced fuel-related downtime by 30% over a six-month period.
Conclusion
The fuel tank on the TD15C may seem like a passive component, but its condition directly affects engine reliability and job site productivity. With proper inspection, cleaning, and upgrades, this system can continue supporting the machine’s rugged performance across decades of service. In heavy equipment, fuel isn’t just a resource—it’s a lifeline, and the tank is where that lifeline begins.