300 kW standby / 270 kW prime · Natural Gas / LPG / Dual Fuel (NG/LPG) · Liquid-cooled
300 kW gaseous-fueled commercial standby generator. Kohler/Rehlko 300REZXC large industrial gaseous unit for major facilities, paralleling applications, and campus power. Note: the 300 kW Kohler gas genset is sold as the 300REZXC, not as 'KG300'.
The 300 kW Kohler/Rehlko gaseous standby generator is sold as the 300REZXC (with sister designations 300REZXD / 300RZXD) — there is no Kohler model called "KG300." We've kept this URL because customers commonly search "Kohler KG300" when comparing 300 kW gas gensets, and we want them landing on accurate information.
The 300REZXC is one of the larger single-unit gaseous gensets in the North American market, powered by a Doosan-built 14.6L turbocharged-aftercooled V8 (Kohler PN GM64103). At this capacity, it competes directly with 300 kW diesel units for campus, hospital, and large commercial applications.
The 300REZXC's 14.6L V8 is a serious stationary engine that demands experienced technicians. We recommend walk-in enclosures at minimum for any 300REZXC installation, and prefer container-style enclosures that allow full 360-degree access. The turbo-aftercooler system adds annual inspection items (charge-air cooler integrity, condensation drain, turbo oil drain lines) beyond what naturally-aspirated KG-class units require.
Engineering specifications
Physical
Wet weight
7,055 lb
Ready to order this model?
Configure your Kohler 300REZXC (300 kW Gas)
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.
Estimate runtime for the Kohler 300REZXC (300 kW Gas)
Adjust load percent and tank size to estimate runtime. Pre-filled with this model's spec where available.
Estimate runtime on this tank
Fuel demand at 75% load
3,150,000 BTU/hr≈ 3150.0 cf/min @ 1,000 BTU/cf
On utility natural gas the runtime is generally unlimited provided the supply line and meter can deliver this BTU/hr at the engine's required inlet pressure (typically 5–14" WC residential, up to 5 psi commercial). Confirm against the OEM's published fuel-pressure spec.
Service intervals
Manufacturer-recommended intervals for the Kohler 300REZXC (300 kW Gas) 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 4000 hours
Air filter
Every 1000 hours
Spark plugs
Every 2000 hours
Major overhaul
≈ 24,000 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
Turbocharger
Oil in intake, reduced power, turbo whine
12,000+
moderate
Spark plugs (8 total, V8)
Individual cylinder misfire under load
2,000+
minor
Intercooler / charge-air cooler
Boost leak, reduced power output
8,000+
minor
Coolant pump
Weeping, bearing noise, overcooling at light load
15,000+
moderate
Parts cross-reference
starting Battery
Group 31 x2 (parallel)
Frequently Asked Questions
Does Kohler/Rehlko make a 'KG300' generator?
No. The KG industrial gaseous lineup tops out at the KG200. The 300 kW Kohler/Rehlko gaseous standby unit is sold as the 300REZXC (and the closely-related 300REZXD/300RZXD), not as a 'KG300'. Spec sheets for these models are published as G4-282 and G4-296.
What is the standby rating of the Kohler 300 kW gas generator?
The 300REZXC is rated 300 kW standby at 60 Hz, powered by a Doosan 14.6L turbocharged-aftercooled V8 at 1800 RPM.
Can the 300REZXC be paralleled?
Yes. With Kohler APM603 paralleling controllers and appropriate switchgear, multiple 300REZXC units can be paralleled for capacity expansion or N+1 redundancy. This is a common configuration for large campuses that prefer gaseous over diesel.
How does this compare to a 300 kW diesel?
A diesel 300 kW unit (such as Kohler's KD300 / 300REOZJ) is more compact and doesn't depend on gas utility. But it requires on-site fuel storage, EPA SPCC plans, annual fuel polishing, and produces visible emissions. The 300REZXC eliminates all fuel-storage concerns but depends on gas utility reliability.
What ATS for 300 kW?
At 480V three-phase: 400-600A ATS. ASCO 7000 Series with bypass-isolation is the typical specification for critical facilities at this capacity.
