Caterpillar · Cat D-Series GC (Diesel)

Cat D400 GC

400 kW standby / 360 kW prime · Diesel · Liquid-cooled

400 kW diesel standby generator from Cat's GC value-engineered line. C13 turbocharged inline-6 with simplified controls for commercial standby.

Standby power
400 kW / 360 kW prime
Voltage options
277/480V, 346/600V
Frequency / Phase
60 Hz · 3-phase
Engine
Caterpillar C13 · 12.5L
EPA / Emissions
Tier 4 Final
standbyCommercialHealthcaremanufacturinghigh-rise
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Overview#

The Cat D400 GC is a 400-kilowatt diesel standby generator — the top C13-powered model in Cat's GC value-engineered line. At 400 kW, it serves hospitals, high-rise buildings, and campus facilities that need substantial standby capacity in a cost-effective package.

100% step-load acceptance#

The D400 GC accepts full rated load in a single step — a critical requirement for facilities with large motor loads or UPS systems that present the full load instantly on transfer. The C13's generous displacement provides the thermal margin for this demanding duty cycle.

Our service perspective#

The D400 GC at the top of the C13 range benefits from careful attention to cooling and air filtration. We service these alongside our standard C13 fleet — same engine, same procedures, same parts. The GC control simplification doesn't affect engine access or serviceability.

Engineering specifications

Physical

Length
148 in
Width
60 in
Height
74 in
Wet weight
9,200 lb

Fuel system & runtime

Fuel use @ full load
28 GPH
Fuel use @ 75% load
21.2 GPH

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Estimate runtime for the Cat D400 GC

Adjust load percent and tank size to estimate runtime. Pre-filled with this model's spec where available.

Estimate runtime on this tank

Estimated runtime

9.3 hours(0.4 days)

Fuel consumption ≈ 21.60 GPH at 75% load. Estimate based on industry-typical 1800 RPM standby curves (≈0.07 GPH/kW at full load). Actual consumption varies by engine, ambient temperature, fuel quality, and tuning.

Service intervals

Manufacturer-recommended intervals for the Cat D400 GC under standby duty. Field intervals may differ based on load profile, ambient conditions, and fuel quality.

Oil & filter
Every 500 hours or 12 months
Coolant change
Every 6000 hours
Air filter
Every 1000 hours
Fuel filter
Every 500 hours
Major overhaul
≈ 20,000 hours
Load bank test
Every 12 months

Common failure modes

What we've seen fail on this platform. Use as a service-planning reference, not a diagnostic — actual failure modes depend heavily on duty cycle and maintenance history.

ComponentSymptomTypical hoursSeverity
Fuel qualityInjector fouling, filter clogging4,380+moderate
TurbochargerReduced power, oil in intake, turbo noise18,000+moderate
Battery banksSlow crank, failed start8,760+minor
Coolant heaterCold start issues, block heater element failure10,000+minor

Frequently Asked Questions

What is the Cat D400 GC?
The D400 GC is Cat's 400 kW value-engineered diesel generator — the top C13 rating in the GC line. It delivers reliable standby power for hospitals, high-rises, and campuses where 400 kW covers full-building essential loads.
Can the D400 GC accept 100% load in one step?
Yes — the D400 GC is designed to accept 100% rated load in a single step per ISO 8528-5 requirements. The C13's 12.5L displacement provides the thermal and mechanical margin needed for instant full-load acceptance.

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