Excavator vs. TLB Engine: What's the Difference and Why Does It Matter?

In the world of heavy machinery, both excavators and TLBs (tractor-loader-backhoes) are crucial workhorses. While they may look similar at first glance—both dig, lift, and move earth—their engines are quite different in design, power, and intended function.

Understanding these differences isn’t just academic. If you’re a contractor, plant hire owner, mechanic, or operator, knowing how the engine of each machine works—and how it impacts performance and maintenance—can help you make better decisions when buying, repairing, or upgrading your fleet.

Let’s unpack the key differences between an excavator and TLB engine—from power output and torque to cooling systems and servicing needs.

1. Purpose-Built for Different Roles

Excavator Engine: Specialised Muscle for Digging

Excavators are designed almost exclusively for digging, trenching, and lifting tasks. Their engines are tailored for:

• High torque at low RPMs, giving them the grunt to operate hydraulic arms and buckets efficiently.

• Continuous operation under heavy load.

• A stationary base, meaning the engine powers hydraulic movement more than it moves the machine itself.

TLB Engine: Jack-of-All-Trades

A TLB, on the other hand, is the Swiss Army knife of construction machinery. It has:

• A tractor base (with wheels) that needs to move across sites.

• A front loader bucket and a rear backhoe arm.

Therefore, the engine is designed to power both mobility and hydraulic functions, requiring a more balanced performance between movement and work functions.

2. Engine Size and Output

Excavator Engines: Bigger, Stronger, Slower

Most 20 to 30-ton excavators run diesel engines ranging between 120 to 200 horsepower, with high torque output ideal for operating massive hydraulic systems. Common OEMs include Isuzu, Cummins, Volvo, Yanmar, and Mitsubishi.

Key traits:

• Larger displacement (often 4.5 to 7 litres).

• Lower RPM operation (usually 1800–2200 RPM max).

• Designed for long hours of operation in a single location.

TLB Engines: Smaller but More Versatile

TLBs typically use smaller engines, often 70 to 100 horsepower, like the Perkins 1104 series, or smaller turbocharged engines from John Deere or Caterpillar.

Key traits:

• Higher RPMs (up to 2500–2800 RPM).

• Optimised for both digging and travel.

• Lighter weight for better mobility.

3. Cooling Systems and Engine Load

Excavator: Designed for Constant Load

Excavators often operate continuously under high hydraulic load. Therefore, they use heavy-duty cooling systems, including:

• High-capacity radiators.

• Oil coolers for hydraulic fluid.

• Engine-driven fans with thermostatic controls.

The engine's load is constant but predictable, making thermal management straightforward but intense.

TLB: Variable Load, Variable Cooling

A TLB might drive to a trench, dig a bit, reverse out, load a truck, then move to the next site. This start-stop duty cycle requires a cooling system that can handle sudden changes in load and engine RPM.

• Fan clutches are more common.

• Radiator sizes are moderate.

• Load demand spikes are more frequent but shorter.

4. Power Delivery and Hydraulics

Excavator Engines: Dedicated Hydraulic Powerhouses

Most of the excavator’s engine power is directed at hydraulic pumps, which in turn power:

• Boom lift.

• Arm and bucket movement.

• Slew (rotation) function.

• Travel motors (if required).

That’s why excavator engines are directly coupled with multiple hydraulic pumps, including:

• A main pump for arm and boom.

• A travel pump.

• A slew pump.

Power is delivered precisely and constantly—think brute strength with finesse.

TLB Engines: Split Responsibilities

TLB engines must:

• Drive the machine via a transmission system.

• Power the hydraulic systems for both loader and backhoe.

• Run attachments via PTO (Power Take-Off), especially in agricultural settings.

This split focus means TLB engines are often less specialized and share load across multiple systems.

5. Emissions and Electronics

Excavator Engines: Advanced Emission Control

Modern excavators (especially Tier 3 and Tier 4 compliant) include:

• Diesel Particulate Filters (DPFs)

• Selective Catalytic Reduction (SCR) systems

• Exhaust Gas Recirculation (EGR)

• Electronic control modules (ECMs) for fine-tuning

They’re engineered to run clean even under high, consistent loads, with tightly controlled fuel-air mixtures.

TLB Engines: Simpler Compliance

Because TLBs are used in more variable operating conditions, emissions systems are generally simpler, although Tier 3/4 compliance is still required for newer models.

Many TLBs:

• Use mechanical injection pumps on older models.

• Have less complex ECMs, especially on pre-2015 machines.

• Feature emissions systems that are easier to bypass or repair in the field.

6. Maintenance and Servicing Differences

Excavator Engines: Long-Haul Durability

Excavators may run for 10,000 hours or more if properly maintained. Their engines are built for:

• Extended oil change intervals.

• Large capacity fuel, oil, and coolant systems.

• Heavier filters (fuel, oil, air).

• Easier access to hydraulic pump drive assemblies.

But the cost of maintenance is higher, and breakdowns can result in costly downtime, especially on remote sites.

TLB Engines: Easier to Service, Shorter Intervals

TLBs are often maintained in workshops or on farmyards. Their engines:

• Have simpler diagnostics (especially on older models).

• Require more frequent oil and filter changes.

• May be cheaper to repair—but not as long-lasting.

TLB engines often need attention every 250–400 hours depending on usage, while excavators can go 500–1000 hours between major services.

7. Fuel Efficiency and Consumption

Excavators: Hungry for Diesel

Due to their size and hydraulic demand, a 20-ton excavator might burn 12 to 20 litres of diesel per hour. Bigger machines use more.

Fuel-saving features include:

• Auto-idle functions.

• Engine deceleration.

• Load-sensing hydraulics.

TLBs: Leaner Burners

A TLB might use 6 to 10 litres of diesel per hour depending on the job. They benefit from:

• Lighter frame and load.

• Less constant hydraulic draw.

• Smaller engine displacement.

This makes TLBs ideal for small to mid-size contractors looking to manage fuel budgets.

8. Interchangeability and Sourcing of Parts

Excavator Engines: More OEM-Specific

Excavator engines are often proprietary, matched to:

• Specific hydraulic pump specs.

• Frame and counterweight balance.

• Cooling requirements.

Interchanging them between brands (e.g., swapping a Volvo D6E into a Komatsu) requires extensive modification, if possible at all.

TLB Engines: More Modular

Many TLBs share common engine platforms—Perkins 1000 series, John Deere PowerTech, or Cummins B-series—which means you can sometimes find interchangeable engines between TLB models, especially if the transmission and hydraulic specs match.

9. Longevity and Rebuild Potential

Excavators: Built for Rebuilds

Excavator engines are usually rebuilt rather than scrapped, especially in South Africa where parts like sleeves, pistons, injectors, and turbos are readily available.

Rebuild kits from OEMs or aftermarket suppliers make it easy to get another 8000+ hours out of a tired engine.

TLBs: Often Replaced Instead of Rebuilt

While rebuilds are possible, many TLB engines are simply replaced with low-hour used units. Cost-effectiveness is the name of the game. Some older machines are even retrofitted with new mechanical diesel engines to avoid electronics altogether.

10. Pricing and Availability of Used Engines

At Vikfin, we’ve noticed:

• Excavator engines command higher prices due to demand and complexity.

• TLB engines are more readily available, with prices 30–50% lower on average.

• Customers often swap out old excavator engines with refurbished OEM options to extend machine life by years.

For example:

• A refurbished Volvo D6E engine for a 20-ton excavator might sell for R90,000–R130,000.

• A rebuilt Perkins 1104 for a TLB might cost R50,000–R70,000.

Conclusion: Horses for Courses

Choosing between an excavator and a TLB isn't just about machine type—it’s about engine design, performance, and function.

Feature	Excavator Engine	TLB Engine
Torque	High at low RPM	Medium to high
Engine Size	120–200 hp	70–100 hp
Hydraulics	High demand	Moderate demand
Cooling	Heavy-duty	Medium-duty
Fuel Use	12–20 L/hr	6–10 L/hr
Mobility	Stationary	Mobile
Maintenance Cost	Higher	Lower
Life Expectancy	10,000+ hrs	6,000–8,000 hrs

Whether you're buying, fixing, or maintaining your machines, understanding these engine differences will help you maximize uptime, reduce fuel costs, and ensure your fleet is fit for purpose.

Looking for a Quality Used Engine?

At Vikfin, we stock a wide range of high-quality used excavator and TLB engines, including brands like Volvo, Perkins, Isuzu, Cummins, and Mitsubishi. All engines are tested, inspected, and ready to breathe new life into your machine—at a fraction of the price of new.

Let us help you get your machines back to work—stronger, faster, cheaper.

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