What is the Cat D300 GC?

The D300 GC is Cat's 300 kW value-engineered diesel generator — the top C9 rating in the GC line. At 300 kW standby, it covers the upper mid-range for hospitals, campuses, and manufacturing facilities.

How does the D300 GC compare to the D350 GC?

The D350 GC steps up to the larger C13 engine (12.5L). If 300 kW covers your load with headroom, the D300 GC on the C9 is more compact and cost-effective. If you need growth capacity beyond 300 kW, the D350 GC provides a larger platform.

Emergency? Call (831) 375-1463 — 24/7 response

Caterpillar · Cat D-Series GC (Diesel)

Cat D300 GC

Name: Cat D300 GC
Brand: Caterpillar
SKU: d300-gc

300 kW standby / 270 kW prime · Diesel · Liquid-cooled

300 kW diesel standby generator from Cat's GC value-engineered line. C9 turbocharged inline-6 with simplified controls for commercial standby.

Cat D300 GC

Specifications & details

Standby power: 300 kW / 270 kW prime
Voltage options: 277/480V, 346/600V
Frequency / Phase: 60 Hz · 3-phase
Engine: Caterpillar C9 · 9.3L
EPA / Emissions: Tier 4 Final

standbyCommercial HealthcaremanufacturingProperty Mgmt

Configure & Quote Download spec sheet

Overview#

The Cat D300 GC is a 300-kilowatt diesel standby generator — the top C9-powered model in Cat's GC value-engineered line. It delivers the maximum output from the 9.3-liter inline-6 in a streamlined package for hospitals, campuses, and manufacturing facilities.

Top of the C9 range#

At 300 kW, the D300 GC extracts maximum performance from the C9 platform before stepping up to the C13 engine. This makes it the right choice when 300 kW covers your standby requirement — you get a proven engine at a competitive price point without oversizing to a larger platform.

Our service perspective#

The D300 GC runs the C9 at its highest GC rating, so adherence to scheduled maintenance intervals is important. We recommend Cat's S.O.S fluid analysis program to track wear trends. The inline-6 configuration provides straightforward access for service.

Engineering specifications

Physical

Length: 136 in
Width: 56 in
Height: 70 in
Wet weight: 7,400 lb

Fuel system & runtime

Fuel use @ full load: 21 GPH
Fuel use @ 75% load: 16 GPH

Ready to order this model?

Configure your Cat D300 GC

Lock the enclosure, fuel system, transfer switch, and add-ons — we'll confirm pricing, availability, and lead time within one business day. Prefer a free-form quote? That option is still here.

Configure & Quote →Just request a quote

Estimate runtime for the Cat D300 GC

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

Estimate runtime on this tank

Generator size

Fuel

Fuel tank capacity

gal

Load

Override full-load GPH (optional)

GPH

Estimated runtime

12.3 hours(0.5 days)

Fuel consumption ≈ 16.20 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 D300 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: ≈ 18,000 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.

Component	Symptom	Typical hours	Severity
Fuel quality	Injector fouling, filter clogging	4,380+	moderate
Turbocharger	Reduced power, oil in intake, turbo noise	18,000+	moderate
Battery banks	Slow crank, failed start	8,760+	minor
Coolant heater	Cold start issues, block heater element failure	10,000+	minor

Frequently Asked Questions

What is the Cat D300 GC?: The D300 GC is Cat's 300 kW value-engineered diesel generator — the top C9 rating in the GC line. At 300 kW standby, it covers the upper mid-range for hospitals, campuses, and manufacturing facilities.
How does the D300 GC compare to the D350 GC?: The D350 GC steps up to the larger C13 engine (12.5L). If 300 kW covers your load with headroom, the D300 GC on the C9 is more compact and cost-effective. If you need growth capacity beyond 300 kW, the D350 GC provides a larger platform.

Similar models

Caterpillar

Caterpillar C9

250 kW diesel with CAT C9 ACERT inline-6. Best resale -- retains 15-25% more than competitors. ~200 US dealers.

250 kW standby · Diesel · Liquid-cooled

250 kW diesel standby for mid-size commercial, schools, and light-industrial with CAT fleet.

The Caterpillar C9 ACERT is a 250 kW standby diesel generator with EPA Tier 3 emissions certification. 8.8L inline-6 with MEUI fuel injection. Ideal for retail, telecom, and light-industrial standby applications.

Tier 33-phasecommercial-standbyretail

Caterpillar

Cat D250 GC

250 kW Cat diesel with C9 inline-6. Steps up to 9.3L displacement. GC value for mid-commercial segment.

250 kW standby · Diesel · Liquid-cooled

250 kW standby for hospitals, campus buildings, and larger commercial facilities requiring institutional power.

250 kW diesel standby generator from Cat's GC value-engineered line. C9 turbocharged inline-6 with simplified controls for commercial standby.

Tier 4 Final3-phasestandbycommercial

Caterpillar

Cat D350 GC

350 kW Cat diesel with C13 inline-6. 12.5L displacement delivers generous reserve capacity. GC pricing.

350 kW standby · Diesel · Liquid-cooled

350 kW standby for hospitals, campuses, and manufacturing where C13 displacement provides step-load confidence.

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

Tier 4 Final3-phasestandbycommercial

Need service or parts for the Cat D300 GC?

We service every major OEM and stock genuine parts for the most common models.

Get A Quote Or call (831) 375-1463