Cummins · Cummins D6 Commercial Diesel

Cummins C35 D6

35 kW standby / 32 kW prime · Diesel · Liquid-cooled

35 kW EPA Tier 3 diesel standby generator with Cummins 4BT3.3-G5 engine and PowerCommand 1.1 control. Sound-attenuated enclosure, liquid-cooled, for small commercial and light-industrial standby.

Cummins Cummins C35 D6 generator — specifications and details
Standby power
35 kW / 32 kW prime
Voltage options
120/240V, 120/208V, 277/480V
Frequency / Phase
60 Hz · 1/3-phase
Engine
Cummins 4BT3.3-G5 · 3.3L
EPA / Emissions
Tier 3
CommercialResidentiallight-industrial
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Overview#

The Cummins C35 D6 (model designation C35D6) is a 35 kW standby diesel generator set powered by the Cummins 4BT3.3-G5 engine -- a 3.3-liter, turbocharged, 4-cylinder industrial diesel running at 1800 rpm. Rated at 43.7 kVA standby and 40 kVA prime at 60 Hz, the C35D6 sits in the middle of the 4BT3.3-based range between the C25D6 and the C40D6.

Standard equipment includes the PowerCommand 1.1 control with integrated voltage regulation and a sound-attenuated enclosure. The unit is EPA Tier 3 certified for stationary emergency standby applications. The 4BT3.3 engine platform provides excellent parts commonality with other units in the 25-60 kW diesel range.

The C35D6 is designed for small commercial standby applications where the load profile exceeds what a 25 kW unit can handle but does not justify the step up to a 50 kW class generator.

Our Service Experience#

At 35 kW, the 4BT3.3 engine is moderately loaded. The turbocharger wastegate actuator should be inspected annually for free movement -- sticking wastegates cause over-boost conditions that can damage the engine. Fuel filter service is straightforward with spin-on Fleetguard elements. On units that exercise infrequently, we recommend a monthly 30-minute loaded exercise to prevent fuel system issues and wet stacking.

Frequently Asked Questions#

How does the C35 D6 compare to the C40 D6? Both share the same 4BT3.3-G5 engine block and the same physical enclosure platform. The C35D6 is calibrated for 35 kW standby output while the C40D6 is calibrated for 40 kW. The C40D6 consumes slightly more fuel at full load. If your peak load is under 35 kW, the C35D6 provides a more fuel-efficient option.

What voltages are available? The C35D6 is available in 120/240V single-phase, 120/208V three-phase, and 277/480V three-phase configurations.

Engineering specifications

Physical

Length
90 in
Width
36 in
Height
50 in
Dry weight
1,600 lb

Fuel system & runtime

Fuel use @ full load
3.2 GPH
Fuel use @ 50% load
1.9 GPH

Documents & downloads

Spec sheets & manuals

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Estimate runtime for the Cummins C35 D6

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

81.0 hours(3.4 days)

Fuel consumption ≈ 2.47 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 Cummins C35 D6 under standby duty. Field intervals may differ based on load profile, ambient conditions, and fuel quality.

Oil & filter
Every 500 hours or 12 months
Air filter
Every 500 hours
Fuel filter
Every 500 hours
Major overhaul
≈ 20,000 hours

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
4BT3.3 turbocharger wastegateOver-boost or under-boost, erratic power output, exhaust smoke—moderate
PowerCommand 1.1 speed sensorEngine hunts at idle, erratic frequency, crank-no-start fault—moderate
Coolant hose connectionsMinor coolant seepage, low coolant warning, overheating risk—minor

Frequently Asked Questions

What engine does the Cummins C35 D6 use?
The C35D6 uses the Cummins 4BT3.3-G5, a 3.3-liter, turbocharged, inline-4-cylinder diesel rated at 1800 rpm. EPA Tier 3 certified. This is the same engine block used across the C25 through C60 diesel range, calibrated for 35 kW standby output.
What are the standby and prime ratings of the C35 D6?
Standby rating is 35 kW (43.7 kVA) at 60 Hz, 0.8 power factor. Prime rating is 32 kW (40 kVA). Both at 1800 rpm.
What are the service intervals for the C35 D6?
Oil and filter changes are due at 500 hours or 12 months, whichever comes first. Air filter and fuel filter replacement at 500-hour intervals. Coolant flush at 3,000 hours or 24 months.
Can OnPoint Generators service the C35 D6 in Northern California?
Yes. OnPoint Generators serves the San Francisco Bay Area, Silicon Valley, and broader Northern California with generator service. We carry 4BT3.3 parts and provide annual maintenance, load bank testing, and emergency response for C35 D6 installations.

Compatible equipment

Transfer switches

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