About The Caterpillar 3406E

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In 1993, Caterpillar began production on the 3406E, the last model engine in the 3406 series. While its predecessors –the A, B, and C– were fully or partially mechanical, the Caterpillar 3406E was the first successful fully electronic motor. The 3406E is usually found in Peterbilt and Freightliner vehicles.

Everything You Need to Know  About This Diesel Engine Icon

“Successful” is almost an understatement; the 3406E is regarded as one of the best engines Caterpillar ever made. Its design combines the reliability of mechanical engines with the new advantages electrical motors bring. This engine was also released pre-emissions standards and these heavy-duty diesel engines were well-received for their performance prior to their restriction.

The Caterpillar 3406E lasted until 1999 when it was replaced by the C15, an engine with comparable parts and horsepower. Because of their similarities, many 3406E, C15, and C15 ACERT engine parts work with each other. Still, be careful when ordering parts, and make sure you have the correct part number. For more comparisons between these Caterpillar engines, check out the blog, The Primary Differences Between Caterpillar 3406E, C15, and C15 Acert Diesel Engines.

A History of the Caterpillar Engine

Over 150 years ago, steam tractors were the primary tool for agricultural development. Far out in the Western United States, in California, the ground was too soft for the tractors to be effective, and they kept sinking. Any potential solutions were too costly and time-consuming. In 1904, Benjamin Holt invented a tractor with a track system instead of wheels. The track system gave the machines a unique movement, often compared to caterpillars, which became the Caterpillar namesake. The product quickly took off for Benjamin Holt’s company: the Holt Manufacturing Company.

Holt Manufacturing Company became successful, but they also developed a strong competitor: C. L. Best Tractor. Both companies were prosperous in the early 1900s, during World War I, but their business drastically fell off afterward. In 1925, both companies merged in an attempt to solve their financial issues. The company adopted its new name from Ben Holt’s iconic tractor design, and Caterpillar was born.

The merger wasn’t quite enough to improve their financial standing. To improve further, they started to manufacture diesel engines in 1931. Then they decided to focus on developing and building construction equipment. Thanks to the post-World War II construction boom, the company saw enormous success.

Caterpillar completely dominated the construction market. They began to branch out in the late 1900s, building truck engines for on and off-highway applications. They also expanded their market worldwide. On-highway diesel engines only made up a small portion of their sales, and in 2008, stricter environmental standards caused them to exit the on-highway diesel market entirely.

What Are Common 3406E Failures?

The Caterpillar 3406E has a good reputation, especially when compared to some other Caterpillar engines. Like all engines, however, it’s not immune from issues.

The 3406E with the 5EK engine serial number is known to have a crankshaft breakage problem. Some 5EKs were made from bad casting, causing the crankshaft to break, usually at journals 1 and 6. Caterpillar handled the problem as it came up, and has been vigilant about replacing defective crankshafts when they’re recognized.

3406E engines are also notorious for oil leaks, typically from the rear engine structures and flywheel housing. Caterpillar initially used flimsy gaskets when building the engine, which was fixed when they upgraded the engine to the C15, replacing the gaskets with seals and using a new block design. As an optional method to check your oil levels, 3406Es have holes in the block, which are stopped with rubber plugs. Over a few years, the rubber plugs will eventually harden, which causes oil leaks.

Aftermarket Improvements for the Caterpillar 3406E Engine

Despite some issues, Caterpillar did a pretty good job with the parts they made for the 3406E. Aftermarket companies can still improve upon the designs and create direct-fit replacement parts that work perfectly with the engine. 

For example, 3406E pistons with forged steel crowns are far superior to the OEM pistons and are available online. Forged parts are stronger and more reliable than cast parts. Forged parts also have uniform, directional grain flow, meaning they conform to the shape of the part and are stronger than OEM pistons. This combination of strength and reliability is important for pistons because they are the heart of an engine, and there’s a lot of intense demand put on their performance.

Sometimes aftermarket improvements aren’t about changing design, value is important too. For example, pins and rollers are rocker arm components that wear down over time. Pin and roller kits for the 3406E are only offered by aftermarket companies; you can buy this kit instead of having the entire rocker arm completely replaced. Buying a kit versus a replacement arm can save you hundreds of dollars.

Caterpillar 3406E Engine Specs

• Fuel: Diesel
• Cubic Inch Displacement: 893
• Cylinder Bore Diameter: 5.400-5.402″ (137.16-137.211 MM)
• Stroke: 6.500″ (165.1 MM)
• Cylinder Configuration: L6
• Engine Comments: 3406E truck, OHC, 24-valve

Caterpillar 3406E Featured Products

Below are some of the most popular 3406E parts we offer. When buying products from HHP, we always require a part number or engine serial number, depending on which product you want. The products below may not work with your specific engine.

Caterpillar 3406E/C15/C15 ACERT Cylinder Head, New
P200010
You’ll find this product in our spotlight on the C15 too, but we promise that it’s worth repeating. This superstar cylinder head fits the 3406E, the C15, and the C15 ACERT. It’s also our best-selling product, and for good reason! For starters, it’s a brand new part, so you get the longest possible life out of it. The forged casting includes more nickel than your standard cylinder head, giving it greater strength and durability. The head also comes fully loaded with valves, springs, retainers, keepers, and cam bearings, saving you the time and expense it takes to track down these parts and install them yourself.l

Caterpillar 3406E Inframe Rebuild Kit
P016482
One of our best-selling rebuild kits for the 3406E. The pistons are manufactured using computer-controlled machining for the most precise specifications. A lot of time has been spent detailing this engine rebuild kit’s piston rings, especially the oil control ring, which has the exact amount of tension needed to seal the cylinder and collect oil. This rebuild kit includes rod and main bearings, which are made with a special blend of metals that give it unmatched strength and durability. If you’re interested in this kit, we require an engine serial number from you to make sure it will properly fit your engine.

Caterpillar C15/3406E Turbocharger with Wastegate, New
P126001
Everybody loves a good turbo. There are so many turbos for sale, but not everyone can do it right. But we can! Just like our featured rebuild kit above, this turbocharger is made in an ISO-certified facility, so you know it’s a quality product. It meets all of the exact specifications for Caterpillar’s OE turbocharger, but only costs a fraction of the price. You can save more money on the same turbo if you purchase a remanufactured version.

Caterpillar 3406E/C15 Fuel Injector, Remanufactured
P016881R
By now the majority of fuel injectors out there for older engines are remanufactured. That’s not necessarily a bad thing. Remanufactured fuel injectors are pretty amazing too. Most of the parts inside them are all new. This injector in particular has a brand new spill valve actuator assembly, NOP spring, washer, shim, stop, and o-rings. All of the remanufactured parts are also cleaned and tested, nozzle included. This injector is manufactured from the same place that supplies injectors for several major OE companies, so they’re comparable to Caterpillar injectors, but at a lower price.

Caterpillar C15/3406E Camshaft, New

P200426

An all-new camshaft that’s undergone thorough testing, including both synthetic performance tests and durability tests, so it will perform flawlessly. The fantastic durability comes from the chilled cast iron and alloy steel used in its production. A quality camshaft like this one enhances your engine’s power, spool-up times, and overall performance. It’s one of the most important parts of your engine.