banner image
banner image
image

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.

 

Engine ModelAdvertised hp (kW)Peak Torque lb-ft (N•m) @ rpmGoverned Speed
ISB XT 350350 (254)750 (1017) @ 18002600
ISB 340 AD*340 (254)660 (895) @ 16002800
ISB 340340 (254)660 (895) @ 16002800
ISB 325325 (243)750 (1017) @ 18002600
ISB 300 AD*300 (224)620 (841) @ 16002600
ISB 300300 (224)620 (841) @ 16002600

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

* Air compressor system options are excluded from these ratings.

 

Specifications.
Advertised Horsepower300-350 hp224-261 kW
Peak Torque620-750 lb-ft841-1017 N•m
Governed Speed2600-2800 rpm
Clutch Engagement Torque400 lb-ft542 N•m
Number of Cylinders6
Oil System Capacity4 U.S. gallons15.1 liters
System Weight1,190 lb540 kg
Engine (Dry)1,150 lb522 kg
Aftertreatment*40 lb18 kg

*Increase over standard muffler

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

 

The Holset Variable Geometry Turbocharger (VG Turbo) provides exhaust braking without additional add-on hardware in the exhaust system and eliminates exhaust brake maintenance. The operator activates braking by using the brake switch in the driver's compartment. ISB exhaust braking assists in stopping the motorhome while reducing wear on the service brakes.

image

 

 

 Miles
Kilometers
Months
Oil and Filter*15,000 mi
24,000 km
12
Fuel Filter*15,000 mi
24,000 km
12
Coolant FilterNone**None**
Overhead Adjustment150,000 mi
240,000 km
48
Coalescing Filter60,000 mi
96,000 km
24
Particulate Filter Cleaning200,000-400,000 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.

Complete warranty details are provided in Cummins Bulletin 3381340

Coach Care™

Coach Care is a network of service centers dedicated to making every maintenance or repair event a pleasant experience. Every Coach Care facility is:

 

  • Designed to meet the needs of motorhome owners
  • A Cummins distributor location, fully certified by Cummins
  • Certified to work on most motorhome chassis
  • Capable of performing many appliance repairs (most locations)
  • Equipped with overnight parking, electrical hookups, sanitation and sewage disposal
  • Located near America's most popular motorhome destinations. Call 1-800-DIESELS (1-800-343-7657) for locations

 

For more information, check out the Coach Care section at www.funroads.com.