Description
About This Engine
The Caterpillar 3406E is the electronically controlled evolution of the legendary CAT 3406 inline-six diesel that powered Class 8 over-the-road trucks, heavy industrial equipment, marine pleasure craft, and standby generators for decades. Produced from 1993 to 1999 in this exact configuration, the 3406E was Caterpillar's answer to growing emissions regulations and demand for electronic engine management while preserving the bulletproof inline-six architecture that made the 3406 family famous.
The 3406E delivers 355 to 550 horsepower and 1,350 to 1,850 lb-ft of torque from 14.6 liters of displacement, depending on the specific calibration and application. Internally it uses a cast iron block, single-piece cast iron head, four valves per cylinder, electronically controlled HEUI injectors, and turbocharged air-to-air aftercooled charge air. The combination of cast iron mass, conservative bore/stroke geometry, and electronic engine control gives the 3406E its trademark reputation: million-mile service life with proper maintenance.
The 2WS Prefix
The 2WS prefix on a 3406E serial number identifies engines built at a specific Caterpillar plant during a specific production window. Many fleet operators and rebuilders specifically seek 2WS prefix units because the parts compatibility, calibration history, and known service characteristics are well documented in the CAT service network. Tell us your truck VIN, equipment serial number, or current engine prefix and we confirm 2WS compatibility before order.
Common 3406E Applications
- Class 8 trucks: Peterbilt 379, Kenworth W900, Freightliner FLD120, International 9900
- Heavy haul: dump trucks, log trucks, water tanker trucks
- Industrial: rock crushers, asphalt plants, large compressors
- Marine: pleasure cruisers, commercial fishing, workboats
- Generator sets: standby and prime power applications
- Off-road equipment: large wheel loaders, articulated dumpers
Signs You Need a Replacement 3406E
- Excessive blow-by past breather, ring or liner wear
- Coolant in oil, head gasket or liner seal failure (rebuild candidate)
- Crank or main bearing knock under load
- Loss of power across all speeds, turbo or fuel system wear
- High oil consumption beyond 1 quart per 8 hours of operation
- Persistent coolant leaks from O-rings on liner pack
What Is Included, What Is Not Included
| INCLUDED | Complete engine: block, crankshaft, rods, pistons, camshaft, head, valve train, oil pan, valve cover, turbocharger, fuel system components present on donor unit, water pump, oil pump. |
|---|---|
| NOT INCLUDED | ECM (sometimes available separately, call to discuss), engine harness, exhaust manifolds (sometimes included), starter, alternator, accessory drive, clutch and flywheel, motor mounts, front cover assembly. |
| Fluids | Drained before shipping. Refill with CAT-spec 15W-40 diesel motor oil. Always pre-lube before first crank. |
| Core Note | No core charge. You are not required to return your old engine. |
The 3406E was a direct fit in the following:
| Peterbilt 379, 378, 357 | 1993 to 1999 (3406E spec'd) |
|---|---|
| Kenworth W900, T800, T600 | 1993 to 1999 (3406E spec'd) |
| Freightliner FLD120, Classic XL | 1993 to 1999 (3406E spec'd) |
| International 9900, 9800, 9300 | 1993 to 1999 (3406E spec'd) |
| Mack RD-Series | Some 1993 to 1999 spec configurations |
| Industrial Equipment | CAT 988, 992 wheel loaders (industrial trim), CAT 5230 excavator (genset trim), various crushers and compressors |
| Marine | Pleasure craft, commercial fishing boats, workboats spec'd for 3406E |
| Generator Sets | CAT 3406E gen-set models 350 kW to 600 kW range |
Application is everything for an industrial diesel of this size. Tell us your truck make, model, transmission, gear ratio, and intended use. We confirm bell-housing pattern, accessory drive, mounting points, and ECM compatibility before every order ships.
Not sure if this fits? Call (240) 301-0095 with your truck VIN or equipment serial number, current engine serial prefix, transmission, and intended application. CAT 3406E configurations vary widely between truck, marine, industrial, and gen-set spec. Our heavy diesel team confirms compatibility before your order ships.
Every used 3406E we ship goes through this process:
- Compression test across all 6 cylinders, pressure per cylinder recorded
- Visual inspection of block, head, and liner pack
- HEUI injector and HEUI pump operation inspected
- Turbocharger shaft play, wastegate, and aftercooler inspected
- Crank and rod bearing inspection where access permits
- Engine hours recorded where ECM data available
- Serial number, prefix, and CAT-spec calibration documented
- Donor application, hours, and operating history disclosed where available
This is heavy industrial diesel. Full inspection documentation, including pictures of bottom-end where access permits, is available on request before order confirmation.
Why Buy From Vaz Auto Solutions
- All 6 cylinders compression tested, results before you pay
- Engine hours documented where ECM data is available
- Serial prefix (2WS or other) confirmed for your spec
- Application fit verified for truck, marine, industrial, or gen-set use
- Free heavy crated freight to all 50 states with care for the engine value
- No core charge, keep your old engine
- 15 day replacement warranty on internal defects
- Heavy diesel experienced support team on the phone, real conversation about CAT specs
Michael Davis (verified owner) –
I needed a new engine for my Freightliner, and I found the 3406E 2WS CAT engine at Find Auto Parts Online. Ordering was easy, and the engine arrived quickly. Installation went smoothly, and since then, the engine has been running strong.
Daisy Michales (verified owner) –
I bought the 3406E 2WS CAT engine from Find Auto Parts Online to replace the old one in my husband’s Kenworth truck. The ordering process was smooth, and the engine arrived on time and well-packed. Installation was straightforward, and we’ve been impressed with its performance.
Larry V., Amarillo TX –
Inframe at 1.4 million miles, sourced a 2WS 3406E from Vaz to keep my Pete on the road. They confirmed the prefix, sent compression numbers, and shared the donor truck’s hour history. Engine arrived crated heavy and was solid. Mechanic dropped it in over a weekend and the truck is back making money.
Doug M., Mobile AL –
Replaced a tired 3406E in my charter boat with a marine-spec unit from Vaz. Application fit was confirmed before shipping, including the marine accessory drive. Heavy crated freight handled professionally. Boat ran sea trials at full RPM for two hours with no issues. Honest team to work with.