The 2021 Peterbilt 579, a flagship vocational and on-highway truck, has been a staple in the trucking industry since its introduction. Known for its distinctive aerodynamic design and driver-centric interior, the 579 is available in various configurations, including day cabs and several sleeper options. While specific trim levels can vary, its popularity stems from a blend of advanced technology, fuel efficiency, and the comfort it offers long-haul drivers. Pricing for a new 2021 model would have varied significantly based on customization, typically starting in the mid-$100,000s and going much higher for premium builds.
The Good
The 2021 Peterbilt 579 boasts exceptional fuel efficiency and robust performance, coupled with a surprisingly comfortable and modern cabin that appeals to drivers' desire for a premium work environment. Its iconic design offers emotional appeal, while the inherent reliability and long-term value provide strong practical benefits for fleet owners.
The Bad
Potential buyers of a 2021 Peterbilt 579 should be aware of the inherent cost of premium trucks, with maintenance and repairs potentially being higher than for less specialized vehicles. Some drivers might find the advanced technology requires a learning curve, and specific component longevity can depend heavily on operating conditions and maintenance schedules.
2021 Peterbilt 579: Quick Overview
- Engine Options: The 2021 Peterbilt 579 typically offered Peterbilt proprietary engines, including the PACCAR MX-13, as well as Cummins ISX15 options. These are heavy-duty diesel engines designed for long-haul and vocational applications.
- Horsepower: Horsepower ratings for the PACCAR MX-13 engine generally ranged from approximately 380 hp to 500 hp, with torque figures often between 1,450 lb-ft and 1,850 lb-ft. Cummins ISX15 engines offered similar, if not higher, power outputs.
- Fuel Economy: While specific MPG figures for heavy-duty trucks are not reported in the same way as passenger vehicles, the 579 is designed for optimal fuel efficiency through its aerodynamic design, efficient powertrains, and advanced driver-assist systems. Real-world fuel economy is highly dependent on load, terrain, driving style, and spec choices, but it is a strong selling point for the model.
- 0-60 Times: 0-60 mph times are not a standard metric for Class 8 trucks, as their purpose is hauling heavy loads over long distances, not rapid acceleration. Performance is measured by ability to maintain speed under load and gradeability.
- Towing Capacity: As a Class 8 heavy-duty truck, the 2021 Peterbilt 579 is designed for immense towing and hauling capacities. Gross Combination Weight Ratings (GCWR) can exceed 80,000 lbs, and with proper configuration, can be rated for much higher, depending on axle configurations, chassis, and government regulations.
- Trim-Level Features: Trims vary significantly based on customer specification. Key features often include advanced aerodynamics, multiple sleeper configurations (e.g., 72-inch UltraCab, 80-inch UltraCab), premium interior appointments with high-quality materials, ergonomic driver seats, advanced infotainment systems with navigation, digital displays, climate control options, and a suite of driver-assistance technologies. Options for advanced safety features like lane departure warning and collision mitigation systems were also available. The focus is on driver comfort and productivity for long-haul operations.
2021 Peterbilt 579 Specifications
Vehicle Information
| Year | 2021 |
| Make | Peterbilt |
| Model | 579 |
| Trim | - |
| Style | - |
| Type | Truck |
| Category | Heavy Truck |
Manufacturing Details
| Made In | United States |
| Manufacturing City | DENTON |
Dimensions
| Doors | - |
| Curb Weight | - |
| Gross Vehicle Weight Rating | 33001 pounds |
| Overall Height | - |
| Overall Length | - |
| Overall Width | - |
| Wheelbase Length | - |
| Standard Seating | - |
Engine & Performance
| Engine | 12.9L L6 DIESEL |
| Engine Size | 12.9L |
| Engine Cylinders | 6 |
| Transmission | - |
| Transmission Type | - |
| Transmission Speeds | - |
| Drivetrain | 6x4 |
Additional Features
| Anti-Brake System | - |
| Steering Type | - |
Pricing
| Manufacturer Suggested Retail Price (MSRP) | - |
| Invoice Price | - |
| Delivery Charges | - |
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What Problems Does the 2021 Peterbilt 579 Have?
While the 2021 Peterbilt 579 is generally considered a reliable and robust truck, like any heavy-duty vehicle, it can experience issues. Specific problems are often related to the complex electronic systems and components common in modern trucks.
One area that can sometimes present challenges is the emissions control system, including Diesel Particulate Filters (DPFs) and Selective Catalytic Converters (SCR). These systems, while essential for meeting environmental regulations, can be prone to clogging or sensor failures if not maintained properly or if the truck is used primarily for short-haul, low-speed operations where regeneration cycles are not completed effectively.
Another area that drivers and fleet managers sometimes report concerns about relates to electrical gremlins or issues with interior electronics. These can range from minor infotainment system glitches to more significant problems with sensor readings or warning lights. These are often difficult to diagnose and can be costly to repair.
While specific widespread issues unique to the 2021 model year are not prominently documented as recurring major failures, it is always advisable to check for any issued recalls. Recalls for heavy-duty trucks are typically related to safety-critical components, such as braking systems, steering components, or potential fire hazards within the electrical system. For example, a recall might address a faulty sensor in the anti-lock braking system (ABS) or an issue with a wiring harness that could lead to intermittent power loss.
Long-term reliability heavily depends on the initial specification of the truck and the rigorousness of its maintenance schedule. Trucks used for demanding vocational work or subjected to harsh operating conditions will naturally experience more wear and tear than those used for consistent, long-haul highway driving. Regular inspections, timely fluid changes, and proactive attention to any minor issues can significantly mitigate the likelihood of major breakdowns and ensure the longevity of the 2021 Peterbilt 579.
How long will the 2021 Peterbilt 579 last?
A well-maintained 2021 Peterbilt 579, especially one used for consistent long-haul highway operations, can realistically be expected to serve for 1.5 million miles or more. Many owner-operators and fleets aim for this mileage before considering a major overhaul or replacement. The durability of the PACCAR MX-13 engine and the robust chassis are significant factors in this longevity. However, weaknesses can emerge over time, particularly with exhaust aftertreatment systems (DPF, SCR), turbochargers, and complex electronic components if maintenance is neglected. Wear and tear on suspension, brakes, and drivetrains are also expected with high mileage. Proactive maintenance, including regular fluid analysis and component inspections, is critical to maximizing its service life and avoiding costly premature failures.
What Technology & Safety Features are Included?
The 2021 Peterbilt 579 was equipped with a suite of modern technology aimed at enhancing driver productivity, comfort, and safety. Standard and optional features included a sophisticated infotainment system, often featuring a large touchscreen display with integrated navigation, Bluetooth connectivity for hands-free calling and audio streaming, and USB ports for device charging. For driver assistance, Peterbilt offered advanced systems designed to reduce fatigue and improve situational awareness. These typically included features such as Lane Departure Warning (LDW) systems, which alert the driver if the vehicle drifts out of its lane, and Collision Mitigation systems, which can automatically apply braking if an imminent collision is detected. Adaptive Cruise Control (ACC) was also an option, maintaining a set speed and distance from the vehicle ahead, which is invaluable on long-haul routes.
Safety features are paramount in heavy-duty trucks, and the 579 was designed with robust construction and safety in mind. While formal crash-test ratings like those for passenger vehicles (e.g., NHTSA or IIHS) are not typically published for Class 8 trucks due to their unique nature and intended use, Peterbilt vehicles are engineered to meet stringent federal safety standards. These include robust frame structures, advanced braking systems (ABS), and optional air disc brakes for improved stopping power. The cab structure is designed for significant impact protection. Additional safety options could include enhanced lighting packages for improved visibility in adverse conditions and robust rearview camera systems. The focus is on preventing accidents through driver assistance technologies and protecting occupants in the event of an incident through structural integrity.
What Colors Options are Available?
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2021 Peterbilt 579 Prices and Market Value
When new, a 2021 Peterbilt 579 would have had a starting price in the mid-$100,000s, but with extensive customization and options, particularly for sleeper configurations, the price could easily climb to $200,000 or significantly more. The used market for 2021 models currently sees prices ranging broadly, often from $80,000 to $150,000 or higher, depending heavily on mileage, condition, engine spec, and remaining warranty. Peterbilts hold their value well due to their reputation for durability and strong brand loyalty. Depreciation is generally slower than for many other commercial vehicles, especially for well-maintained trucks with desirable specifications. Factors affecting resale value include total mileage, engine hours, maintenance history, tire condition, and the presence of any aftermarket modifications or desirable factory options. Trucks with PACCAR MX-13 engines are typically sought after.
2021 Peterbilt 579 Cost of Ownership
Owning a 2021 Peterbilt 579 is a significant investment, with ownership costs being on the higher side compared to lighter-duty commercial vehicles. Insurance premiums are substantial due to the high value and risk associated with heavy-duty trucking. Fuel costs are a major operational expense, though the 579's efficiency helps mitigate this. Maintenance and repair costs are also considerable, with specialized parts and labor required for a Class 8 truck. However, its long-term durability and strong resale value can make it economical relative to its peers for businesses that maximize its operational lifespan and efficiency. Regular, preventative maintenance is key to controlling long-term costs.
2021 Peterbilt 579 Fuel Efficiency
Fuel Type
Diesel
Fuel Capacity
-
City Mileage
-
Highway Mileage
-
2021 Peterbilt 579 Warranty
Basic
Original warranty
0 months / No data
Estimated remaining
Expired
Powertrain
Original warranty
0 months / No data
Estimated remaining
Expired
Rust
Original warranty
0 months / No data
Estimated remaining
Expired
2021 Peterbilt 579 Insurance
Insurance for a 2021 Peterbilt 579 is moderately priced, reflecting its status as a Truck with strong safety ratings and
reasonable repair costs.
reasonable repair costs.
How Does the 2021 Peterbilt 579 Compare to Other Truck?
The 2021 Peterbilt 579 competes directly with other premium Class 8 conventional trucks from manufacturers like Kenworth, Freightliner, and International. In terms of performance, Peterbilt trucks, including the 579, are renowned for their robust powertrains, often featuring PACCAR or Cummins engines that deliver excellent torque and pulling power, making them highly competitive with rivals like the Kenworth T680 or the Freightliner Cascadia.
Features-wise, the 579 is designed with a strong emphasis on driver comfort and advanced technology. Its aerodynamic design and well-appointed interiors are often cited as strengths, rivaling the premium offerings found in the Kenworth T680, which shares many components with the Peterbilt. The Freightliner Cascadia also offers a competitive set of technology and comfort features, often at a slightly more aggressive price point, making it a strong value proposition for some buyers. International's LT Series provides a solid contender with good fuel efficiency and driver amenities.
Reliability is a strong suit for Peterbilt and Kenworth, both benefiting from the PACCAR shared platform and engineering. They are typically considered among the most reliable in the industry, with durable components and strong build quality. While Freightliner and International also offer reliable trucks, Peterbilt and Kenworth often command a slight edge in perceived long-term durability and build finesse, contributing to their premium pricing.
Price is where the 579 often sits at the higher end of the spectrum. Peterbilt trucks are positioned as premium, so they may be more expensive new and used compared to a similarly equipped Freightliner Cascadia or International LT.
**Alternatives:**
* Kenworth T680: A very similar truck, sharing many platforms and powertrains with the 579. It's an excellent alternative, often considered nearly interchangeable in terms of capability and comfort, sometimes with slight differences in interior styling or option availability.
* Freightliner Cascadia: A highly popular and often more budget-friendly option. The Cascadia offers competitive fuel efficiency and a comprehensive suite of technology and safety features, making it a strong contender, especially for fleets prioritizing cost-effectiveness.
* International LT Series: A capable truck with good fuel economy and driver comfort features. It presents a strong alternative, particularly if specific International dealer network support or pricing is more favorable.
Ultimately, the 2021 Peterbilt 579 is a top-tier choice for those seeking premium performance, exceptional driver comfort, and proven reliability, provided the budget allows for its premium positioning.
Final Verdict: Is the 2021 Peterbilt 579 a Good Truck?
The 2021 Peterbilt 579 is ideal for owner-operators and fleet managers who prioritize driver comfort, fuel efficiency, and long-term durability, especially for long-haul operations. It's a premium truck that justifies its cost through its build quality, advanced features, and strong resale value. It is worth buying for those who can leverage its strengths for consistent, profitable business. Buying used can offer significant value, particularly for trucks with lower mileage and well-documented maintenance. A used 2021 579, perhaps a day cab or a moderate sleeper configuration, can be an excellent investment. For new purchases, highly specified sleeper models offer the ultimate in driver comfort for extended road time. It represents a solid, albeit premium, choice in the heavy-duty truck market.
Simon A
Simon is a contributor to VinCheck, where he provides articles and reviews on various automotive topics. His work focuses on delivering accurate and up-to-date information about used cars, helping readers make informed decisions.