Ask an old hand which big Cat they would keep forever and a lot of them will say the 3406E. It has the pull, it has the sound, and it has a long record of running hard for years. If your truck or machine needs one, we have a Caterpillar 3406E engine for sale, tested, matched to your serial number and shipped to buyers anywhere in the world.
Ready to buy? See the price, photos and stock for our fairly used Caterpillar 3406E engine for sale in the shop, or send your engine serial number through our contact page and we will reply with a written quote.
We are an engine supplier and that is all we do. A Caterpillar 3406E engine for sale is one of the engines owner operators, haulage companies and equipment yards ask us for most, usually because they want to keep a good older truck working instead of buying a new one.
This guide covers the 3406E specs, the trucks it fits, the serial number prefixes, the 40 pin and 70 pin ECM difference, the common problems, how we test and how buying from us works.
Why a Caterpillar 3406E Engine for Sale Is Still in Demand
The 3406 family goes back to the early 1970s. The 3406A, B and C were mechanical engines, and they built Cat a reputation in heavy trucks. The 3406E came in the early 1990s and was the first of the line with full electronic control. It kept the same basic 14.6 litre inline six layout but added electronic unit injectors and an engine computer that could manage timing and fuel far more precisely.
That change gave drivers more power, better fuel economy and features like cruise control and idle shutdown, while keeping the toughness of the older engines. It became one of the favourite engines in long nose trucks, and many are still running today with more than a million miles behind them.
So why is a Caterpillar 3406E engine for sale still worth buying in 2026? Three reasons. It has no EGR, no particulate filter and no DEF, so it is simple to run in places with older emissions rules. It is easy to rebuild, with parts widely available. And it fits straight back into the many trucks that were built with it, so a swap is usually simple.
Caterpillar 3406E Engine Specifications
These figures apply to the common truck versions. Ratings vary with the year, the software and the application, so we always confirm details from the data plate before we quote any Caterpillar 3406E engine for sale.
| Engine type | Inline 6 cylinder, four stroke turbo diesel |
| Displacement | 14.6 litres (893 cubic inches) |
| Bore x stroke | 137.2 mm x 165.1 mm (5.4 in x 6.5 in) |
| Valve train | Overhead camshaft, 4 valves per cylinder |
| Fuel system | Electronic unit injectors, mechanically actuated |
| Engine control | ADEM II (40 pin) and later ADEM III (70 pin) |
| Horsepower | About 355 to 600 hp depending on rating |
| Peak torque | Up to about 1,850 lb-ft on popular truck ratings |
| Truck serial prefixes | 1LW, 2WS, 5EK, 6TS |
| Dry weight | Roughly 2,800 to 3,000 lb |
| Production | Early 1990s to around 2000, followed by the C15 |
The serial number prefix is the single most useful detail when you shop for a Caterpillar 3406E engine for sale. It tells you roughly when the engine was built and which parts it uses.
Which Trucks and Machines Use the 3406E?
The 3406E was fitted to a long list of trucks, mostly conventional Class 8 tractors and heavy haulers:
- Peterbilt 377, 378, 379 and 385
- Kenworth W900, T600 and T800
- Freightliner FLD, Classic and Century Class
- Western Star 4900 series
- International 9000 series, including the 9400 and 9900
- Some Volvo, Mack and Sterling builds for special orders
- Industrial power units, generator sets, pumps, crushers and marine engines
The Kenworth W900 and the Peterbilt 379 are the classic homes for this engine, and you will find them working with a 3406E in many countries. Because the engine went into so many chassis and machines, mounts, oil pans, front covers and accessories differ. That is why we always ask about your truck or machine before quoting a Caterpillar 3406E engine for sale.
3406E Serial Number Prefixes Explained
Cat uses a three character prefix at the start of the engine serial number. For truck engines the common ones are:
- 1LW, an early truck prefix from the mid 1990s.
- 2WS, another truck prefix, common in heavy haul and higher horsepower ratings.
- 5EK, a very common prefix from the mid to late 1990s.
- 6TS, a later prefix found on many late 1990s and 2000 trucks.
Industrial and marine 3406E engines carry their own prefixes. When you send us your full serial number we can match the right block, head and parts arrangement. A Caterpillar 3406E engine for sale with the same prefix as your old engine is the easiest swap.
40 Pin vs 70 Pin ECM
Earlier 3406E engines use the ADEM II computer with 40 pin connectors. From around 1999 many moved to the ADEM III with 70 pin connectors. The two are not plug and play. If your truck was wired for a 40 pin engine and you buy a 70 pin engine, you need the matching ECM and harness, or a conversion.
It sounds like a small detail, but it causes more failed swaps than anything else. Every Caterpillar 3406E engine for sale we quote lists the ECM type so you know exactly what you are getting.
Known 3406E Weak Spots
The 3406E is tough, but even a good Caterpillar 3406E engine for sale can have a few weak points worth checking.
- Injector sleeves (cups). Worn or leaking sleeves can let coolant into the fuel or combustion gases into the coolant.
- Cracked heads. Severe overheating can crack the head between the valve seats. Look for coolant loss and pressure in the cooling system.
- Water pump and oil cooler leaks. Common as the engine ages. Both are easy to fix if caught early.
- Front gear train noise. High mileage engines can develop gear lash. We listen for it when we run them.
- Turbo wear. Shaft play and oil leaks at the turbo are worth checking on any older diesel.
- Wiring and sensors. Old harnesses and connectors cause many running faults that look worse than they are.
How We Test Every Caterpillar 3406E Engine for Sale
Before any Caterpillar 3406E engine for sale leaves our yard, we do the following:
- Record the full serial number, the arrangement number and the rating from the plate.
- Check compression or run a cylinder cut-out test where the engine can run.
- Check the oil for coolant, fuel or metal.
- Pressure test the cooling system where possible to look for head or sleeve leaks.
- Run the engine where we can and check oil pressure, blow-by and smoke.
- Check the turbo for play and the front gear train for noise.
- Photograph the engine from all sides, including the serial plate.
You get these results and photos with your quote. You can read more in our guide to tested used engines.
What Comes With the Engine
Most of our 3406E stock is sold as a complete engine, which normally includes the block, head, injectors, turbo, manifolds, oil pan and front cover. Some engines come with the ECM. Accessories like the air compressor, fuel pump, starter and alternator vary from engine to engine.
If you only need a long block or a bare block, we can quote that too. A long block often saves money when the accessories on your old engine are still good.
Used, Rebuilt or Remanufactured?
Used engines come out of working trucks and machines and are sold after testing. They are the cheapest option and suit trucks with a few good years left.
Rebuilt engines have been opened up and fitted with new wear parts such as liners, pistons, rings, bearings and gaskets.
Remanufactured engines are brought back to factory measurements across the board, and they cost the most.
Most buyers choose a tested used Caterpillar 3406E engine for sale because it gets the truck working for the least money. If you are planning a long life for the truck, a rebuilt engine can make sense. We will give you honest advice either way.
7 Checks Before You Buy Any Caterpillar 3406E Engine for Sale
1. Match the serial prefix
Before you pay for a Caterpillar 3406E engine for sale, compare its prefix with your old engine. Same prefix usually means the easiest fit.
2. Confirm the ECM type
Know whether your truck is wired for 40 pin or 70 pin. It saves a lot of trouble later.
3. Ask for test results
A seller who tested their Caterpillar 3406E engine for sale can show you compression or cut-out results and oil pressure.
4. Check for coolant in the oil
Coolant in the oil can point to sleeve, cooler or head trouble. Ask about it directly.
5. Ask for real photos
Insist on pictures of the actual engine, including the data plate.
6. Know what is included
Two listings for a Caterpillar 3406E engine for sale can look the same and still be very different deals once you count the turbo, injectors, ECM and accessories.
7. Read the warranty
Know how long it is and what it covers. Our used engine warranty guide explains what to look for.
What Affects the Price
The price of a Caterpillar 3406E engine for sale depends on the prefix, the rating, the mileage or hours, the condition and what comes with it. High horsepower truck engines and low hour industrial engines usually cost more. A complete engine with ECM costs more than a long block. Because 3406E engines are no longer built, good ones hold their value well.
Freight is the other big cost. A crated 3406E is heavy, so shipping to your country can add a good amount to the total. We include freight options in your quote. For more on this, see our guide on replacement engine cost.
How Long Does a 3406E Last?
A 3406E that is serviced on time and kept cool can run a million miles or more before it needs major work. The ones that fail early usually overheated, ran with dirty air filters, missed oil changes or sat idling for long periods. In dusty or hot regions, air and coolant care matter even more.
When you compare a Caterpillar 3406E engine for sale, the hours or miles on the ECM help, but how the engine was looked after matters more. That is why we test rather than relying on the numbers alone.
Habits that keep a 3406E healthy
- Change oil and filters on time with a good heavy duty oil.
- Keep coolant clean and at the right strength.
- Do valve and injector adjustments at the right intervals.
- Keep the air filter sealed and replace it often in dusty conditions.
- Watch temperature gauges and fix overheating at once.
Industrial, Generator and Marine 3406E Engines
A lot of requests for a Caterpillar 3406E engine for sale come from outside trucking. The 3406E powered generator sets, pumps, crushers, drilling rigs and boats. These versions often have different flywheels, cooling systems and governors from truck engines, and their ratings differ too.
A truck engine is not always a direct swap into a generator or boat. Tell us what the engine will drive and we will look for the right arrangement. Low hour standby generator engines can be a great buy, since many spent most of their life waiting for a power cut.
Worldwide Shipping
We ship engines to buyers across Africa, Europe, the Middle East, Asia, Latin America, the Caribbean and North America. Every engine is drained, sealed, strapped or crated and shipped by sea or road freight with tracking. We prepare the export paperwork and work with your clearing agent.
Read our shipping policy for timing details, and ask for a port or door price with your quote.
Installation Tips
When your Caterpillar 3406E engine for sale arrives, these steps help the install go well:
- Flush the radiator and cooling system. Old debris can damage a good engine.
- Clean the charge air cooler if the old engine failed with oil or metal in the intake.
- Fit new filters and fresh oil, and prime the fuel system before first start.
- Check the ECM parameters, such as road speed and cruise limits, suit your truck.
- Idle the engine to temperature and check for leaks before loading the truck.
New to buying engines online? Our guide on how to buy a used engine online explains the whole process.
3406E vs C15 and Other Engines
The 3406E was followed by the C15, which kept the 14.6 litre size and added changes for newer emissions rules, later including ACERT technology. Early C15 engines are close relatives of the 3406E, while later ACERT engines are more complex. If you want simple and proven, the 3406E is hard to beat. You can learn more about the maker on the Caterpillar Inc. page.
If you are comparing brands, the Cummins N14 and the Detroit Diesel Series 60 were the 3406E’s main rivals in the same trucks. We also sell the Caterpillar C13 and the older Caterpillar 3306.
Rebuild Your Old Engine or Replace It?
This is the question most owners wrestle with. An in-frame rebuild keeps your own engine and can be cheaper on paper. But the truck sits in the shop while the work is done, and once the engine is open the bill often grows. A cracked head, a scored crank or a damaged block can turn a planned rebuild into a much bigger job.
Swapping in a tested Caterpillar 3406E engine for sale is usually faster. The replacement is ready to go, you know its condition up front, and the truck can be back at work in days instead of weeks. Your old engine can also have value as a core, which brings the real cost down further.
Our rough rule: if the block or crank is damaged, or the truck earns money every day it runs, replacing usually wins. If the engine only needs a top end job and you have a good mechanic with time, a rebuild can make sense. Tell us what happened to your engine and we will give you a straight opinion.
Fuel Economy and Power Settings
One of the best things about a 3406E is that much of how it drives is set in the software. Road speed limits, cruise speed, idle shutdown and some power settings can be adjusted with the right service tool. A Caterpillar 3406E engine for sale that came out of a fleet truck may have conservative settings, while one from an owner operator might be set up for maximum power.
Fuel economy depends a lot on gearing, load, terrain and driving style. Many drivers report figures in the five to seven miles per gallon range in highway work, with better numbers on light loads and flat roads. Running the engine in its torque band and avoiding long idling makes a real difference.
Keep in mind that turning the power up also means more heat and more load on the engine. If you plan to change the rating on your Caterpillar 3406E engine for sale, make sure the cooling system, clutch and drivetrain can handle it.
Parts that matter for power and economy
- Healthy injectors with correct trim codes loaded in the ECM
- A turbo with no shaft play and no oil leaks
- A clean, leak free charge air cooler
- Correct valve and injector adjustment
- A free flowing exhaust and clean air filter
Questions We Ask Before Quoting
To find the right Caterpillar 3406E engine for sale for you, we usually ask:
- What is the full serial number of your old engine?
- What truck or machine is it going into, and what year?
- Is your truck wired for a 40 pin or 70 pin ECM?
- Do you want a complete engine or a long block?
- Which port or city should we ship to?
With that information we can send a quote with photos, test results and freight costs, usually the same day.
Other Heavy Diesel Engines We Sell
We also supply the Detroit DD15, the Volvo D13 and the Cummins ISX15. See our full range of used diesel truck engines and our guide to low mileage used engines.
Why Buy From NJ Global Auto Parts
We test our engines, describe them honestly and ship worldwide. We confirm the fit before you pay. Every Caterpillar 3406E engine for sale from us comes with real photos, a written quote, tracking and a written warranty. Our refund and returns policy is open to read before you order.
Frequently Asked Questions
What years was the 3406E built?
From the early 1990s until around 2000 for trucks, when the C15 took over. Industrial versions ran a little longer.
How much horsepower does a 3406E make?
Truck ratings run from about 355 to 600 hp. Many common truck engines are rated between 435 and 550 hp.
Is the 3406E better than the 3406B?
The 3406E has electronic control, better fuel economy and more power. The 3406B is fully mechanical and simpler. Both are strong engines.
Does your Caterpillar 3406E engine for sale include the ECM?
Some do and some do not. Your quote will say which.
Do you ship worldwide?
Yes. We ship to most countries and prepare the export paperwork.
How do I pay?
Bank transfer only. The details come with your written quote.
How do I get a quote?
Send your serial number or truck details through our contact page or call +1 (209) 733-0882.
Get Your Truck Back to Work
A good truck should not sit because of a tired engine. If you need a Caterpillar 3406E engine for sale that has been tested, matched to your truck and shipped with tracking, get in touch today. We will confirm the fit, send photos and give you a straight price, wherever you are.