Remanufactured Cummins ISL 8.9L (543 ci) Engine For Sale
2002–present — 260–380 hp | 660–1,150 lb-ft
The Cummins ISL 8.9L is the go-to engine for medium-heavy-duty applications that need more power than the ISB but don't require the full Class 8 capability of the ISX. Introduced in 2002 as a successo...
Starting from $7,000 – $12,000 — 1-Year Unlimited Mileage Warranty
Cummins ISL Technical Specifications
About the Cummins ISL Engine
The Cummins ISL 8.9L is the go-to engine for medium-heavy-duty applications that need more power than the ISB but don't require the full Class 8 capability of the ISX. Introduced in 2002 as a successor to the ISC 8.3L, the ISL fills the critical gap between medium-duty and heavy-duty applications. It powers vocational trucks, refuse vehicles, transit buses, fire trucks, and luxury motorhomes. The ISL is particularly popular in the RV market, where its combination of power, smooth operation, and compact size makes it ideal for diesel pushers. In 2013, Cummins introduced the ISL9 designation (later rebranded L9) with improved fuel economy and emissions technology. The ISL has earned a reputation for reliability in demanding vocational applications where engines operate under high loads and frequent stop-and-go cycles.
Cummins ISL Strengths
- Perfect power-to-weight ratio for medium-heavy-duty applications
- Compact size fits in chassis where the ISX is too large
- Excellent fuel economy for its displacement class
- Smooth, quiet operation — ideal for motorhome and transit bus applications
- Proven reliability in demanding vocational duty cycles (refuse, fire, construction)
- Lower operating costs compared to larger displacement engines
Common Cummins ISL Issues (Addressed in Our Remanufactured Engines)
- EGR cooler failure on 2007-2010 models can cause coolant contamination
- Turbo bearing failure at high mileage leads to oil consumption and smoke
- Injector O-ring leaks can cause hard starting and fuel dilution
- Aftertreatment system (DPF) requires periodic cleaning in stop-and-go applications
- Oil cooler housing gasket leaks on some model years
- Crankshaft position sensor failure can cause intermittent no-start conditions
Vehicles with the Cummins ISL
Available Cummins ISL Remanufactured Engines
Cummins ISL Buying Guide
When purchasing a remanufactured Cummins ISL, identify whether your application uses the ISL (pre-2013) or ISL9/L9 (2013+) variant, as they have different emissions equipment. For motorhome applications, verify the horsepower rating matches your coach — RV versions typically run 340-380 hp. For vocational trucks, the ISL is often paired with Allison automatic transmissions. A quality remanufactured ISL should include rebuilt injectors, a new or rebuilt turbo, and updated EGR components.
Frequently Asked Questions — Cummins ISL
How much does a remanufactured Cummins ISL engine cost?
A remanufactured Cummins ISL 8.9L engine typically costs between $7,000 and $12,000 depending on the model year, application, and horsepower rating. Motorhome versions may cost more due to specific accessory drive configurations. All our ISL engines are dyno tested and include a comprehensive warranty. Call (631) 991-7700 for an exact quote.
What is the Cummins ISL used in?
The Cummins ISL 8.9L is used in a wide range of medium-heavy-duty applications including vocational trucks (refuse, fire, construction), transit buses, school buses, motorhomes, and medium-duty commercial trucks. Popular truck brands include Freightliner M2, Kenworth T370/T470, Peterbilt 348/365, and International WorkStar.
Is the Cummins ISL reliable?
Yes, the Cummins ISL is known for excellent reliability, particularly in vocational applications. It was designed for demanding duty cycles with frequent stop-and-go operation, heavy loads, and PTO usage. With proper maintenance, ISL engines regularly exceed 500,000 miles in commercial service.
What is the difference between ISL and ISL9?
The ISL9 (introduced in 2013, later rebranded L9) is an updated version of the ISL with improved fuel economy, updated emissions technology, and refined combustion. The core engine architecture is similar, but the ISL9 has updated injectors, turbo, and aftertreatment system. Parts are not always interchangeable between the two.
How long does a Cummins ISL engine last?
A well-maintained Cummins ISL can last 400,000 to 700,000+ miles depending on the application. Motorhome applications with lighter duty cycles often see longer engine life, while vocational trucks in demanding stop-and-go service may need overhaul sooner. Regular maintenance is key to longevity.
What replaced the Cummins ISC?
The Cummins ISL replaced the ISC 8.3L in 2002. The ISL increased displacement from 8.3L to 8.9L, added common rail fuel injection, and improved power output. The ISL offers significantly better fuel economy and emissions performance compared to the ISC it replaced.
Cummins Troubleshooting Guides
Cummins ISX Problems
6 common ISX issues: EGR cooler, injectors, cam followers, turbo failures.
Read Guide →Cummins ISB / B6.7 Problems
EGR, turbo VGT, injector, DPF/SCR, and oil leak issues explained.
Read Guide →Diesel Engine Cost Guide
Complete pricing for remanufactured Cummins engines by model.
Read Guide →Reman vs Rebuilt Engines
Which option is right for your Cummins? Compare quality, cost, and warranty.
Read Guide →Installation Guide
Step-by-step guide for installing your remanufactured Cummins engine.
Read Guide →