ISB for Motorhome (EPA 07)

Power 300 - 350 hp
224 - 261 kW
Torque 620 - 750 lb-ft
841 - 1017 N•m
Certification EPA 2007

Select an Application


The Cummins ISB has a long reputation as the most fuel efficient engine in the motorhome industry. The ISB utilizes the Cummins Variable Geometry Turbocharger (VG Turbo) and High Pressure Common Rail (HPCR) fuel system to produce outstanding driveability, integrated exhaust braking and, arguably, the quietest diesel engine in a motorhome today. Its industry-leading fuel economy, extended oil change intervals and minimal maintenance requirements also make the ISB the low-cost-of-ownership leader in its class.

Every ISB rating has been developed to optimize every aspect of the engine's operation, utilizing Cummins comprehensive in-house design approach to every engine system from the air intake to the exhaust system. Integration of Cummins advanced electronic controls, VG Turbo, high-pressure fuel system, combustion technology and exhaust aftertreatment is how the ISB delivers on the performance and value expectations of the motorhome owner. And the ISB does it while being certified and compliant to the toughest standards, the 2007 EPA emissions regulations.

Plus, you get exclusive Cummins programs like Coach Care™ to meet your service needs as you travel across North America in your motorhome. All backed by the most extensive customer support network in North America.

For Cummins-branded merchandise, electronic tools, literature and more, visit our PowerStore web site.

Advertised Horsepower 300-350 hp 224-261 kW
Peak Torque 620-750 lb-ft 841-1017 N•m
Governed Speed 2600-2800 rpm  
Clutch Engagement Torque 400 lb-ft 542 N•m
Number of Cylinders 6  
Oil System Capacity 4 U.S. gallons 15.1 liters
System Weight 1,190 lb 540 kg
Engine (Dry) 1,150 lb 522 kg
Aftertreatment* 40 lb 18 kg

*Increase over standard muffler

Cummins is a pioneer in product improvement. Thus specifications may change without notice.

Engine Model Advertised hp (kW) Peak Torque lb-ft (N•m) @ rpm Governed Speed
ISB XT 350 350 (254) 750 (1017) @ 1800 2600
ISB 340 AD* 340 (254) 660 (895) @ 1600 2800
ISB 340 340 (254) 660 (895) @ 1600 2800
ISB 325 325 (243) 750 (1017) @ 1800 2600
ISB 300 AD* 300 (224) 620 (841) @ 1600 2600
ISB 300 300 (224) 620 (841) @ 1600 2600

Click any of the above ratings to download an electronic PDF spec sheet.

* Air compressor system options are excluded from these ratings.

Oil and Filter* 15,000 mi
24,000 km
Fuel Filter* 15,000 mi
24,000 km
Coolant Filter None** None**
Overhead Adjustment 150,000 mi
240,000 km
Coalescing Filter 60,000 mi
96,000 km
Particulate Filter Cleaning 200,000-400,000 mi
320,000-640,000 km

*Oil, fuel and water filters should be changed at every oil change.

**If engine is equipped with an optional coolant filter, it will need to be replaced on the same intervals as the oil filter.

For additional details download the ISB RV Maintenance and Operation Guide.

When it's time for maintenance, be sure to visit your authorized Cummins distributor or dealer.

Cummins ISB is fully compatible with long-life coolant/antifreeze formulas which allow changes out to 6 years. Follow maintenance guidelines recommended by the manufacturer for safe use with extended service intervals.

For complete maintenance information, please consult your Owner's Manual or Operations and Maintenance Manual.

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