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Cummins ISL (8.9 L) Engine Program

8.9 Liter ISL Cummins Engines for Sale

Cummins ISL (5.9L) EngineThe Cummins ISL is a six-cylinder diesel engine that boasts a low weight, compact design, and highly efficient 8.9 liter configuration. Due to the ISL being lighter than others in its class, gives it an edge by awarding its operators all the benefits that come with running a high-performance engine that is both reliable and durable. The ISL was originally launched for municipal buses in 1999. The engine itself was designed to fill the void left by the discontinued L10, despite this, its characteristics align more so with the ISC.

The ISL had its fair share of challenges, in its early years the coolant would wet the soot in the EGR stream that caused a buildup on the grid heater which subsequently caused plugging. However, Cummins promptly rectified this by revising a few of the parts and adapting the software. Regardless, the Cummins ISL appears to have earned its title of a remarkable engine as the vast amount of reviews depict it to be one of a kind.

Cummins ISL Engine Applications and Uses

  • AERA Association MemberTransit Bus
  • Fire & Emergency
  • Medium-Duty Truck
  • Motorhome & RV
  • Motorcoach

Common ISL Cummins Engine Problems & Failures

Listed Below are some engine problems and failures commonly reported by customers who wish to replace their either worn out or problematic ISL. Unfortunately, some of the issues listed below could lead to the permanent damage of your engine, but some can be rectified if caught in their infancy.
Cummins ISL

  • Camshaft Failure
  • Crankshaft Failure
  • Lifter/Roller Failure
  • Connecting Rod Failure
  • Spun Crankshaft Bearings
  • Cracked Cylinder Head(s)
  • Scored Pistons and Liners
  • Over Fueling
  • Lack of oil or oil pressure
  • Extreme Blow By
  • Dropped Valves

ISL Cummins Replacement Options

When it comes to the health of your engine there could be an overabundance of complications, worst case scenario, you could be left with an issue where your choices are limited exclusively to replacement. However, less stressing situations may just require you to replace some parts or components, or maybe your 8.9 Cummins engine just needs a new lease of life needing no more than a mere refreshment. Of course, cost, time, and availability will determine your decision making so let us inform you of the pro’s and con’s of a new Cummins ISL engine from the dealer vs used or reman long block option.

ISL Cummins Replacement Options Chart

Cummins ISL (5.9L)Cummins ISL 8.9L Remanufacturing Process

A remanufactured Cummins ISL long block is a great replacement for someone who has experienced catastrophic internal engine failure but still has good reusable external components that can be saved from their old motor. Long blocks are also a good alternative when trying to reduce costs in the hunt for a new engine.

Our team of machinists and engine builders complete a full-core tear down, cleaning, inspection, and machining of the engine before it leaves our facility to ensure perfection each and every time.

However, it is important to mention that all of our Cummins ISL remanufactured long blocks are constructed with a combination of both reman and new parts. However, we do not recondition or refurbish former engine parts but rather completely rebuild the old ISL motor back to OEM specs.

Thorough Cleaning

First, every ISL engine is wholly stripped. Blocks, heads, rods, crankshafts and camshafts are thoroughly cleaned in a chemical jet wash or hot tank to remove all impurities that could accelerate both early component and engine failure.


Prior to being thoroughly inspected by our quality control department, crankshafts are precision machined to exact tolerances, polished & magnafluxed.

Cylinder Heads

Heads are resurfaced to ensure a proper sealing surface with the block and a finish consistent with today's new gasket materials. Valve height is mic-d and every head is vacuum tested to assure accurate valve seating.

Cylinder Blocks

Blocks consist of magnetic particle which are inspected for cracks and imperfections. Cylinders are then bored and honed and inspected to precise tolerances. Torque plate honing is performed on particular engines to avoid the chances of cylinder head distortion after the head is bolted and torqued to the block. This process eliminates a major cause of engine blow-by on Cummins ISL. Block surfaces are machined and then inspected to ensure proper finish.


Camshafts are carefully inspected and precisely machined to provide correct lift. Lobs are measured with a micrometer to make sure OEM tolerances are met.

Connecting Rods

Connecting rods are first cleaned, then machined to O.E.M. specifications of 8.9 Cummins, and before being honed to the standard diameter of previous equipment for even distribution of stress on the bearings. New bushings are fitted and machined in all bushed rods. Every rod is carefully inspected for bend and twist.

New Cummins ISL Parts

Our ISL long block engines receive a standard set of new parts such as pistons and rings, bearings, gaskets and seals, and liners. These new parts assure good performance and reliability throughout the lifetime of your engine. The new parts are a combination of OEM and Aftermarket when available.

Request a Quote

Please fill out the form below with your information and request. A member of our staff will be with you shortly.

Remanufactured Engine Standards

To remanufacture is to make as close to new as possible. Wearable parts are automatically replaced.

All Cummins 8.9 ISL core material is thoroughly inspected and examined against original equipment specifications for correct dimensional tolerances. Replacement parts are new or re-qualified. If new, parts are made in the same production processes as original equipment. Testing is performed to manufacturer specifications and original production standards.


Reman ISL Long Block Parts List:

ISL Cummins Engine

  • Complete Loaded Cylinder Head
  • Crankshaft
  • Connecting Rods
  • Cylinder Block
  • Intermediate Cover
  • Timed Front Gear Group
  • New Upper and Lower Gasket Set
  • Camshaft
  • Followers/Lifters
  • Pistons
  • Liners
  • Rings
  • **1 Year Warranty

*Note we can provide new oil pumps, oil coolers, water pumps, turbos, injectors and fuel pumps for an additional cost with the long block but will not come assembled to the engine. In addition to diesel ISL engines, we also provide natural gas ISLG 8.9 L replacements.

**First 6 Months Parts & Labor, Second 6 Months Parts Replacement Only. Ask your sales representative for a full copy of our remanufactured long block warranty.

Cummins ISL Spec

Engine Data

Engine Type Four Stroke, In-Line, Six Cylinder, Turbocharged/Charge Air Cooled
Displacement 8.9 L  (541 ci)
Bore 4.49 in (114 mm)
Stroke 5.69 in (145 mm)
Compression Ratio 16.6:1
Horsepower 280 - 400 HP
Torque Range 700 to 1255 ft-lbs
Weight (Dry) 706 KG
Cylinders 6 Inline
Cylinder Head Material Cast Iron
Engine Block Material Cast Iron, Removable Liners
Give us a call today at 844-340-4114 for immediate sales and support for the Cummins 4BT, Cummins 6BT, 6CT, ISC, 855, QSB 4.5 L or CAT 3306. If you have any questions check out our FAQ Page. We are always ready to help or just listen to your crazy off-roading adventures!

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