Cummins Engines for Sale
Reconditioned, used and new Cummins diesel engines for trucks, buses, plant, workboats and generators. Send the ESN and CPL from the dataplate, or just the make, model and year of the vehicle or machine, and we'll confirm the build and a price.
Most people looking at Cummins engines for sale have a vehicle or machine stood still. A 7.5-tonner with a dropped valve, a midibus off the road with no spare in the depot, a dumper that should be on hire, a workboat tied up when it should be fishing. Every day it sits there costs money. Send the dataplate numbers and we'll come back with the right build, a price and a despatch date.
Commercial Engines supplies reconditioned, remanufactured, used and new Cummins engines across the UK. Most enquiries are for the B Series, from the mechanical 4BT and 6BT to the electronic ISBe and QSB, followed by the bigger C Series units such as the 6CT and ISCe. We also rebuild Cummins engines in our workshop when keeping your original block is the better spend.
Which Cummins Have You Got? Find the ESN and CPL
Two Cummins engines with the same name can be very different underneath. An ISBe in a truck and a QSB in an excavator share a block design but differ in fuel system, ECU calibration, sump, flywheel housing and ancillaries. Even two 6BT engines can differ in injection pump, turbo and power rating. Buying on the model name alone is how an engine turns up that won't bolt in or won't talk to the vehicle.
Cummins makes this easy if you know where to look. The dataplate, on the front gear (timing) housing or the rocker cover, depending on the build, carries an eight-digit ESN (engine serial number) and a CPL (control parts list) number. The CPL tells us exactly how the engine was built at the factory. Send a clear photo of the plate, plus the make, model and year of the vehicle or machine, and we'll confirm the build before we quote. If the plate has gone, the ESN is also stamped on the block, and we can work from that.
- ESN and CPL checked before we quote
- Sump, flywheel housing and mounts matched to the application
- Electronic engines matched to the right ECU and calibration
- Ancillaries agreed up front: what moves over and what's included
Cummins B Series: 4BT, 6BT, ISBe and QSB
The B Series is the Cummins diesel engine we're asked for most. The mechanical engines came first: the 4BT (3.9 litre, four cylinder) and the 6BT (5.9 litre, six cylinder), with TA versions carrying an aftercooler. A Cummins 6BT engine is simple, tough and still common in older trucks, buses, dumpers, compressors, generators and boats, which makes it one of the best candidates for reconditioning. The electronic versions followed. In UK trucks and buses you'll find the ISBe, the European-emissions version of the ISB, in 4.5, 5.9 and 6.7 litre forms. Off-road, the same family is sold as the QSB (QSB4.5, QSB5.9 and QSB6.7) in excavators, loaders, telehandlers, tractors and pumps. Most use common-rail injection (early QSB5.9s used a VP44 rotary pump), and all need an ECU, so the calibration has to suit the vehicle or machine.
- Reconditioned Cummins 4BT and 6BT engines for older trucks, plant, gensets and boats
- ISBe engines for 7.5 to 18-tonne trucks and midibuses, matched by CPL
- QSB engines for construction and agricultural machinery
- Used B Series engines where the machine doesn't justify a rebuild
- New engines where the vehicle is under warranty or no good core exists
Cummins C and L Series: 6CT, ISCe, ISLe and QSL
For heavier work, the 8.3 litre C Series picks up where the B Series stops. The mechanical 6CT and 6CTA run in older trucks, buses, loading shovels, generators and workboats. The electronic ISCe found its way into double-deck buses such as the Dennis Trident, and into trucks and coaches. The 8.9 litre L Series (ISLe on the road, QSL off it) took over from the C Series in many later trucks and buses. These are bigger, dearer engines, so the reconditioned or exchange route usually makes more sense than new. Give us the ESN and CPL and we'll quote what's available.
Cummins Marine Engines for Workboats and Boats
Cummins marine engines are common in UK fishing boats, workboats, pilot boats and larger cruisers. The mechanical 4BTA, 6BTA and 6CTA marine engines are still widely fitted, and the electronic QSB and QSL marine engines cover newer vessels. A boat that can't go out isn't earning, so we'll quote a rebuild of your existing Cummins boat engine alongside any replacement that suits the engine bed, gearbox and coupling, and say which gets you back on the water sooner. For other makes, see Marine Diesel Engines under Related Services below.
Stock, Lead Times and Delivery
If the engine you need is on the shelf, we'll say so and give you a despatch date. If it has to be sourced or rebuilt, you'll get the lead time and the price before you commit. If it's a CPL we can't match quickly, we'll tell you that on the first call.
We deliver to depots, yards, sites, farms and boatyards anywhere in the UK. Lines are open Monday to Friday 8am to 5:30pm and Saturday 9am to 1pm. Ring with the ESN and CPL and we'll check stock and price while you're on the phone where we can.
- Despatch date confirmed when you order
- Delivery to your depot, yard or site anywhere in the UK
- Price and lead time agreed before you order
- Fitting advice from people who know the engine
Reconditioned Cummins Engines: What a Proper Rebuild Includes
A Cummins can look tidy on a pallet and still have a loose dowel pin or tired liners inside. Before you buy reconditioned Cummins engines from anyone, ask for a list of what was replaced. Ours should show:
- Block and head stripped, cleaned and crack checked
- B Series: parent bores honed or sleeved, with new pistons and rings
- 4BT and 6BT: the timing case dowel pin (the well-known "killer dowel") checked and secured
- C Series: wet liners replaced, with new seals and liner protrusion set
- P7100 or VP44 pumps, or common-rail injectors, bench tested
- Crank reground where needed, with new mains and big-ends, and the engine run before despatch
Cummins Engine Price: What Changes the Cost
A 4BT for a dumper and an ISCe for a double-decker sit at opposite ends of the price range, so any single figure would mislead you. Send the dataplate details and we'll price each route that fits. These are the things that move the number most:
- Series and build: C and L Series engines cost more than B Series, and electronic more than mechanical
- Condition: used, reconditioned, remanufactured or new
- Exchange: returning your old engine as a core usually brings the price down
- Ancillaries: whether the turbo, fuel pump, starter, alternator and ECU are included
- Availability: common ISBe and 6BT builds are easier to supply than rare or obsolete ones
Reconditioned, Remanufactured, Used or New?
A depot bus doing 60,000 miles a year and a dumper used twice a week need different answers.
| Option | Relative Cost | Condition Known? | Best For |
|---|---|---|---|
| Reconditioned | Mid | Yes, rebuilt and run before despatch | Working trucks, buses, plant and boats with years left in them |
| Remanufactured | Mid to high | Yes, built to factory specification | High-mileage fleets and high-hours machines |
| Used | Lowest | Partly: inspected, not rebuilt | Older or low-use vehicles and machines |
| New | Highest | Yes | Vehicles under warranty or where no good core exists |
*Ask for more than one option on the same quote and we'll set them side by side.
Cummins Engines for Sale by Series
Send the ESN and CPL, or the vehicle or machine make, model and year, and we'll confirm the exact build, stock and price.
B Series (mechanical)
4BT, 4BTA, 6BT and 6BTA for older trucks, buses, dumpers, compressors, gensets and boats.
ISBe
4.5, 5.9 and 6.7 litre electronic engines for UK trucks and midibuses, matched by CPL.
QSB
QSB4.5, QSB5.9 and QSB6.7 for excavators, loaders, telehandlers, tractors and pumps.
C & L Series
6CT, 6CTA, ISCe, ISLe and QSL for heavier trucks, double-deck buses, plant and workboats.
Marine
4BTA, 6BTA, QSB and QSL marine engines, rebuilt or replaced to suit the engine bed and drive.
Not Sure?
Send a photo of the dataplate and we'll identify the engine for you.
Applications & Use Cases
Wherever a diesel engine is critical to operations — on the road, on the water, in the field, or in a plant room — we have the right engine for the job.
Trucks & Light Commercials
ISBe and B Series engines for 7.5 to 18-tonne trucks and other light and medium commercials.
Buses & Coaches
ISBe engines for midibuses and ISCe engines for double-deckers, matched to the chassis.
Plant & Construction
QSB and B Series engines for excavators, loaders, dumpers and compressors.
Workboats & Boats
Cummins marine engines for fishing boats, workboats and larger cruisers.
Generators
Genset-rated 4BTA, 6BTA and 6CTA builds. Full options are on our Generator Engines page.
Workshops & Trade
Garages and fitters buying Cummins engines for their own customers' vehicles.