What is the 6252-71-1110 Fuel Injection Pump ?
The 6252-71-1110 Fuel Injection Pump is a high-pressure, in-line fuel injection pump designed specifically for the Komatsu SAA6D125 engine, which powers the Komatsu PC490LC hydraulic excavator. This pump is a genuine Komatsu part (also cross-referencing to Bosch or Zexel equivalents) and belongs to the P-series or PE-series in-line pump family. Unlike the distributor-type pumps discussed previously, the 6252-71-1110 is an in-line pump with a separate plunger and barrel assembly for each of the engine’s six cylinders.
The SAA6D125 is a 6-cylinder, 4-stroke, turbocharged, air-to-air aftercooled diesel engine with a displacement of 11.04 liters (or 15.2 liters depending on variant – the SAA6D125 typically is 11.04L for PC490LC). It produces up to 354 HP (264 kW) and is renowned for its durability in heavy earthmoving applications. The 6252-71-1110 pump is a mechanical, electronically governed unit (often with a built-in fuel cut solenoid and timing advance device). It delivers fuel at pressures up to 1,000–1,200 bar to the injectors via high-pressure lines.
For owners of a Komatsu PC490LC excavator – a 50-ton class machine used in mining, quarrying, and large construction projects – this pump is the heart of the fuel system. A failing pump leads to poor performance, excessive fuel consumption, and costly downtime. Aftermarket alternatives compatible with Komatsu specifications, such as those from Rsolid engine parts, offer the same OEM fit and performance at a fraction of the cost, with no core deposit required.
How Does the 6252-71-1110 Fuel Injection Pump Work ?
The 6252-71-1110 injection pump is an in-line, jerk-type pump. Its operation is fundamentally different from rotary distributor pumps. Here is a step-by-step breakdown tailored to the SAA6D125 engine:
Fuel Supply: A low-pressure feed pump (often gear-type, mounted on the injection pump) draws diesel from the tank through a primary filter and water separator. It supplies fuel to the pump housing at approx. 2–4 bar.
Individual Plunger Compression: The pump has six independent plunger and barrel assemblies – one for each cylinder of the SAA6D125. Each plunger is driven by a camshaft inside the pump. As the cam lobe lifts the plunger, the fuel in the barrel is compressed to 1,000–1,200 bar (14,500–17,400 psi).
Injection Timing & Cutoff: At the precise moment (determined by the cam profile and timing shims), a delivery valve opens, sending the high-pressure fuel through a steel line to the corresponding injector. At the end of the plunger stroke, a helix (spill port) in the plunger uncovers a vent hole, rapidly dropping pressure and stopping injection.
Governor Control: The pump includes a mechanical or electronic governor (Komatsu uses both depending on emission tier). For the SAA6D125 in PC490LC, it is typically an all-speed mechanical governor with a vacuum-operated boost compensator (for altitude and turbo boost). The governor adjusts the fuel rack position (which rotates each plunger to change the effective stroke) to maintain desired RPM under varying loads.
Timing Advance: A hydraulic timer (or electric actuator on later models) advances injection timing as engine speed increases, optimizing combustion for power and efficiency.
When the 6252-71-1110 pump wears – common after 8,000–12,000 hours on a PC490LC – symptoms include:
Hard starting (especially cold).
Uneven idle or misfire in one or more cylinders.
Black smoke under load (over-fueling).
Loss of digging power and slow swing/boom response.
Increased fuel consumption (often 15–25% higher).
Replacing it with a quality compatible pump restores factory fuel delivery and timing.
Advantages of the 6252-71-1110 Fuel Injection Pump (for Komatsu PC490LC SAA6D125)
Why should you choose this specific pump for your Komatsu excavator? The advantages are critical for heavy equipment owners.
1. Direct OEM Fitment for Komatsu PC490LC
The 6252-71-1110 pump matches the exact mounting flange (SAE 6-bolt), drive coupling splines, and injector line port spacing of the original Komatsu pump. No adapter plates, line bending, or shimming required – a true bolt-on replacement.
2. Restored Engine Power & Hydraulic Performance
The SAA6D125 engine produces 354 HP at 1,950 RPM. A worn pump can reduce effective horsepower by 20–30%, directly impacting hydraulic functions (bucket breakout force, arm curl speed, and track drive power). A new pump restores the machine’s rated productivity.
3. Significant Fuel Savings for Heavy Earthmoving
The PC490LC consumes 30–45 liters of diesel per hour under load. A failing pump increases consumption by 15–25% – up to 10 extra liters per hour. Over a 2,000-hour operating year, that’s 20,000 liters wasted. Replacing the pump pays for itself in fuel savings within months.
4. Reduced Black Smoke & Compliance with Emission Standards
Many mines and construction sites enforce strict opacity limits. A worn pump causes visible black smoke, leading to fines or machine grounding. A properly calibrated 6252-71-1110 pump ensures clean combustion and compliance with Tier 2 or Tier 3 emission standards.
Applications of the 6252-71-1110 Fuel Injection Pump
This pump is engine-specific for the Komatsu SAA6D125. Which machines use that engine? Below is the comprehensive application list.
Komatsu Excavators (Primary Market)
Komatsu PC490LC-10, -11, -8 (and later -8E0): The most common application. The PC490LC is a 50-ton class excavator with long undercarriage.
Komatsu PC400LC (some variants): Some PC400LC models use the SAA6D125 (verify before ordering).
Komatsu PC450LC (some years): Overlap with PC490; always check engine model.
Komatsu Wheel Loaders
Komatsu WA500-5, -6, -7: Some WA500 series loaders are powered by the SAA6D125 engine.
Komatsu WA480-5: May use the same pump, but confirm.
Komatsu Bulldozers
Komatsu D375A (some series): The D375A often uses the SAA6D140 or SAA6D125 – verify engine tag.
Komatsu D275A: Less common, but possible.
Industrial & Stationary Applications
Komatsu SAA6D125 generator sets (prime or standby power).
Komatsu SAA6D125-powered pumps, crushers, or drilling rigs.
Important cross-reference: The 6252-71-1110 Komatsu part number may be superseded or interchangeable with:
Supplier of the 6252-71-1110 Fuel Injection Pump: Why Rsolid Engine Parts?
For heavy equipment owners, downtime is expensive. Choosing a reliable supplier for your 6252-71-1110 pump is as important as the pump itself. Rsolid engine parts has become a trusted source for Komatsu fuel systems worldwide. Here are their specific advantages for this pump.
1. 100% Bench-Tested to Komatsu / Bosch Standards
Every Rsolid 6252-71-1110 pump is tested on a Bosch EPS 815 or Hartridge 500 series test bench. The detailed test report includes:
Delivery volume per cylinder (mm³/stroke) at idle, peak torque, and rated speed.
Governor start point, full-load, and idle speed settings.
Timing advance curve (degrees vs. RPM).
Feed pump output pressure and flow.
Leakage at full pressure (1,200 bar).
2. Exact OEM Fitment for PC490LC
Rsolid engineers have reverse-engineered the pump using original Komatsu castings, or they source OEM-spec housings from ISO9001-certified foundries. The mounting flange, drive coupling spline, and injector line port positions match the SAA6D125 timing gear housing exactly. No line bending, bracket modification, or shimming required.
3. No Core Charge – Keep Your Old Pump
Unlike many rebuilders that charge a $500–$800 core deposit, Rsolid supplies new production pumps with no core charge. You can keep your old pump as a spare or rebuild it later. This is especially valuable for remote job sites where sending back a core is logistically difficult.
4. 12-Month Unlimited Hour Warranty
Rsolid covers any manufacturing defect, seal leak, calibration drift, or premature wear for one full year (unlimited operating hours). This includes free replacement if the pump fails due to internal component failure (excluding contaminated fuel or improper installation). For mining and construction, this warranty provides peace of mind.
