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Heavy equipment fleet operators praise the Komatsu SAA6D107E as a reliable workhorse. Powering everything from the ubiquitous PC200-8 excavators to WA320 wheel loaders and D61 dozers, this engine is the heartbeat of job sites across the country.

Operators love it for its torque, and mechanics generally appreciate its serviceability. But industrial environments are tough, and even the mighty SAA6D107E has its breaking point. On the job site, a patched-up engine simply won't cut it. Let's take a look at this engine and how we remanufacture and re-engineer it to eliminate factory weaknesses so you can avoid downtime.

Komatsu SAA6D107E Failure Points (and Choate Fixes)

There are a few consistent pain points we hear about over and over when it comes to this platform. Here is how we address them for a better-than-OE engine:

Fuel System and Rail Pressure Issues

One of the most common fault states operators face is the CA559 or CA2249 rail pressure code, which indicates that the High-Pressure Common Rail (HPCR) system is failing to maintain the commanded fuel pressure. In demanding environments, poor fuel quality, water contamination, and microscopic dirt particles bypass standard micron filters and wreak havoc on the HPCR pump and injectors. These contaminants will:

• Score the incredibly tight-tolerance plungers and erode the injector seats.
• Lead to excessive return flow, uncontrolled over-fueling (visible as black smoke or unburnt hydrocarbons), and ultimately, cylinder wash.

Cylinder wash occurs when raw, unatomized diesel fuel washes away the protective oil film on the cylinder walls, causing metal-to-metal friction, accelerated piston ring wear, and a loss of compression.

Fuel System and Rail Pressure Fixes: Because failing fuel injectors can fatally compromise the engine's lower end (via cylinder bore wash and oil dilution), we:

• Meticulously blueprint the engine block and rotating assembly to ensure your new mechanical foundation is completely free of previous damage.
• Correct cylinder wall scoring and ensure optimal piston ring sealing by ensuring every cylinder is precision CNC diamond-honed. We achieve an exact, mathematically calculated cross-hatch angle and surface roughness (Ra) profile to guarantee superior oil retention and immediate ring seating.

By establishing this perfect cylinder geometry and correcting factory imbalances in the rotating assembly, we make sure your remanufactured engine operates with enhanced harmonic stability, maximum compression, and a longer operational lifespan than a stock unit.

Turbocharger Wear and Airflow Restrictions

Dust is the enemy of forced induction. Dirty air intake systems and heavy dust conditions disrupt the precise tolerances of the compressor blades and lead to rapid erosion of the compressor wheel, commonly referred to as 'dusting.' As the turbocharger works harder to build boost, it elevates Exhaust Gas Temperatures (EGTs) and drops power output.

Furthermore, on newer Dash 2 and Dash 3 models equipped with Komatsu Variable Geometry Turbochargers (KVGT), the exhaust turbine faces its own harsh reality. Excessive unburnt hydrocarbons (soot) and extreme thermal cycling cause carbon fouling. This buildup leads to mechanical binding and actuation failure of the vane mechanisms, destroying the engine's ability to regulate exhaust backpressure and boost.

Turbocharger and Airflow Fixes: To combat these airflow restrictions, we focus on the engine's breathing and thermal management. Our upgraded, in-house machined cylinder heads are Magnetic Particle Inspected (MPI) and hydrostatically pressure-tested to guarantee the structural integrity of the casting and water jackets, ensuring they are entirely crack- and leak-free. We also re-engineer and blueprint the valve seats to drastically improve airflow and handle extreme exhaust gas temperatures.

Thermal Stress and Head Gasket Leaks

Prolonged lugging (operating at high throttle positions under heavy load while constrained to low RPMs) creates massive thermal stress across the cylinder head. Thermal cycling subjects the cylinder head and engine block to unequal rates of expansion and contraction. Over time, this repeated micro-flexing overcomes the head bolts' clamping force, causing warping of the mating surfaces between the head and block.

Once these deck surfaces lose their perfect flatness, the clamping load on the head gasket's structural fire ring is compromised. Inevitably, you'll have combustion gases breaching the cooling system, coolant ingress into the cylinders, and ultimately, a blown head gasket.

Thermal and Gasket Solutions: Deck precision is everything. We heavily invest in the structural geometry of the engine:

• We CNC-machine and true all block and cylinder head mating surfaces to exact tolerances, often within 0.002 inches from end to end.
• We meticulously calibrate the cutting feeds and speeds to achieve a highly specific surface roughness (Ra) profile. A precise micro-finish is critical for the proper crush, adhesion, and sealing of modern Multi-Layer Steel (MLS) head gaskets.

The result is a head gasket seal capable of withstanding the immense cylinder pressures and thermal expansion inherent in severe-duty industrial use.

Komatsu Diesel Engines from Choate Engineering

Don't let a downed machine eat your profits. Check out our entire industrial diesel engine lineup online to experience these proven benefits:

• Real Problem Solving: We specialize in solving the real problems found inside today’s most popular diesel power plants. Our engines are fully remanufactured and re-engineered to outperform factory designs.
• Advanced In-House Machining: Our reman diesel engines are designed and machined entirely in-house using advanced 4- and 5-axis CNC equipment, flow benches, and precision balancing technology. We eliminate OEM design flaws.
• True Remanufacturing: We reman diesel engines - meaning every detail is inspected, machined, and upgraded to meet or exceed OEM specifications. Unlike a simple rebuild, which may reuse parts and skip precision machining, our reman process corrects known weak points.

Remember, when it's time for a repower, you can't just drop any SAA6D107E into your excavator. From the Tier 3 Dash 1 to the Tier 4 Final Dash 3 (with KDPF and SCR systems), the electronics and exhaust components vary wildly. Contact our dash designation experts if you have questions. We know the unique problems of every Komatsu data plate dash number and build the solution right in. Order today!