ISL for Motorhome (EPA 07)


ISL for Motorhome (EPA 07)Cummins ISL has the ideal performance for larger, luxury motorhomes. With ratings from 370-425 hp, it has the power to accelerate, at any speed. 1200 lb-ft of peak torque lets you climb steep grades even when towing. The ISL also has a very stout engine brake which provides greater peace of mind on those steep downhill runs. Plus, the engine braking capacity reduces wear on your service brakes, lengthening service intervals and saving you money. And with 20,000-mile (32,000 km) oil change intervals, the ISL makes your maintenance budget go farther.

The ISL was 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 ISL delivers on the performance and value expectations of the motorhome owner. And the ISL does it while being certified and compliant to the toughest standards, the 2007 EPA emission 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.


Cummins PowerSpec is an electronic tool that makes it possible to tailor the operation of Cummins engines in every on-highway application.

Available for: On-Highway, Recreational Vehicle, Motorhome Engines

See ISL PowerSpec Engine Features


Advertised Horsepower 370-425 bhp 276-317 kW
Peak Torque 1200 lb-ft 1627 N•m
Governed Speed 2200 rpm
Clutch Engagement Torque 550 lb-ft 746 N•m
Number of Cylinders 6
Oil System Capacity 7.3 U.S. gallons 27.6 liters
System Weight 1,685 lb 765 kg
Engine (Dry) 1,635 lb 742 kg
Aftertreatment* 50 lb 23 kg

*Increase over standard muffler

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

Product Finder Specifications

Certification Level EPA 2007
Power 370 - 425 hp / 276 - 317 kW
Torque 1200 lb-ft / 1627 N•m


Engine Model Advertised hp (kW) Peak Torque lb-ft (N•m) @ rpm Governed Speed
ISL 425 425 (317) 1200 (2237) @ 1300 2200
ISL 400 400 (298) 1200 (1966) @ 1300 2200
ISL 370 370 (336) 1200 (2237) @ 1300 2200

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


Oil and Filter 20,000 mi
32,000 km
Prefilter/Water Separator Fuel Filter* 20,000 mi
32,000 km
Pressure-Side Fuel Filter* 20,000 mi
32,000 km
Coolant Filter None** None**
Overhead Adjustment 150,000 mi
241,500 km
Coalescing Filter 80,000 mi
128,000 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 ISL RV Maintenance and Operation Guide.

See your Owner's Manual for every detail. And when it's time for maintenance, be sure to visit your authorized Cummins distributor or dealer.

Cummins ISL 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.

Brochures Available

Title Bulletin Number Request View  
Diesel Versus Gasoline RV Flyer 4971524 Request View  Download
National Overhaul Warranty For MidRange Engines Flyer 4021552 Request View  Download
NRP - DPF There Is A Difference Brochure 5410774 Request View  Download
NRP - DPF There Is A Difference Brochure (French) 5410815 Request View  Download
NRP - DPF There Is A Difference Brochure (Spanish) 5410816 Request View  Download