Hard Starting Issues on the Volvo L90D Wheel Loader

[MikePhua]

Volvo’s L90D and Its Role in Mid-Size Material Handling
The Volvo L90D wheel loader was introduced in the early 2000s as part of Volvo Construction Equipment’s D-series, which emphasized fuel efficiency, operator comfort, and hydraulic precision. With an operating weight of approximately 15,000 kg and a net engine output of around 150 hp, the L90D was designed for versatile tasks ranging from aggregate loading to snow removal and forestry support. Volvo, founded in 1832 and headquartered in Sweden, has sold thousands of L90-class loaders globally, with the L90D earning a reputation for reliability and smooth control.
The L90D features a torque converter transmission, load-sensing hydraulics, and a spacious cab with ergonomic controls. Its Tier 2-compliant diesel engine delivers consistent torque, but like many older machines, it can develop hard starting issues over time—especially in cold climates or after prolonged idle periods.
Terminology Notes

• Preheater: A device that warms intake air or coolant to aid cold starts.
  
• Glow Plug: A heating element used in diesel engines to raise combustion chamber temperature before ignition.
  
• Fuel Lift Pump: A low-pressure pump that transfers fuel from the tank to the injection pump.
  
• Cranking RPM: The rotational speed of the engine during starter engagement, critical for ignition timing.
  

Symptoms and Operational Impact
Hard starting in the L90D typically presents as:

• Extended cranking time before ignition
  
• White smoke during startup, indicating incomplete combustion
  
• Engine stalling shortly after firing
  
• Starter motor overheating or battery drain
  
• Reduced productivity due to delayed warm-up cycles
  

In one case, a quarry operator in Alberta reported that his L90D required multiple start attempts each morning. After inspecting the fuel system, he discovered that the lift pump was leaking internally, causing air intrusion and delayed fuel delivery. Replacing the pump and bleeding the lines resolved the issue.
Field Anecdote and Improvisation
During a winter road maintenance project in Finland, an L90D failed to start after sitting overnight in -20°C conditions. The operator used a portable coolant heater and wrapped the fuel lines with thermal tape. After 45 minutes of preheating, the loader started smoothly and completed its shift without further issues. The crew later installed an automatic block heater and fuel line insulation to prevent recurrence.
Root Causes and Diagnostic Strategy
Hard starting in the L90D can stem from multiple sources:

• Weak battery or poor terminal connections reducing cranking RPM
  
• Faulty glow plugs or preheater system failing to warm combustion chamber
  
• Air leaks in fuel lines or filter housing causing vapor lock
  
• Dirty or clogged fuel filters restricting flow
  
• Low compression due to worn piston rings or valve seating
  

To diagnose:

• Measure battery voltage under load; should remain above 10.5V during cranking
  
• Inspect glow plug resistance and verify preheater operation
  
• Check fuel filter condition and replace if discolored or waterlogged
  
• Bleed fuel system to remove trapped air
  
• Perform compression test on all cylinders; values below 300 psi may indicate wear
  

If the engine starts but stalls, monitor fuel pressure at the injection pump inlet. A drop below 5 psi during cranking suggests lift pump failure or blockage.
Preventive Maintenance and Recommendations

• Replace fuel filters every 500 hours or seasonally
  
• Test glow plugs and preheater monthly during winter
  
• Use winter-grade diesel with anti-gel additives in cold climates
  
• Install block heaters and battery warmers for sub-zero operations
  
• Inspect fuel lines for cracks or loose fittings quarterly
  
• Clean battery terminals and check cable resistance annually
  

For machines stored outdoors, consider using insulated engine covers and scheduling warm-up cycles before shift start.
Design Simplicity and Serviceability
The L90D’s engine bay is designed for accessibility, with grouped filters and diagnostic ports. The fuel system uses mechanical injection, allowing field repairs without electronic calibration. The starter motor and glow plug harness are reachable without cab removal, and Volvo provides detailed service manuals for troubleshooting.
Operators appreciate the loader’s smooth hydraulic response and visibility, but starting reliability is essential for maintaining uptime—especially in seasonal or remote operations.
Conclusion
Hard starting in the Volvo L90D is often a symptom of fuel delivery issues, weak electrical systems, or cold-weather stress. With methodical inspection and preventive upgrades, the problem can be resolved and long-term reliability restored. In mid-size loaders, ignition is more than a button—it’s the gateway to productivity. The L90D proves that even seasoned machines need a little warmth and attention to keep moving forward.