Mercedes CLS Mk3 (2018-2023) Used Guide: Engines, Costs, Tips

The Mercedes-Benz CLS Mk3, produced from 2018 to 2023, redefined the ‘four-door coupe’ segment with its sweeping lines, advanced powertrains, and opulent cabin. This generation built on the model’s reputation for blending grand tourer comfort with sports car thrills, making it an appealing choice on the used market today. Whether you’re drawn to its effortless acceleration or plush ride, this guide covers everything from engines and features to ownership costs and common issues.

Design and Exterior Highlights

The CLS Mk3 stands out with its aerodynamic silhouette, featuring a long hood, sleek roofline, and sculpted flanks that emphasize its premium status. Measuring over 5 meters in length, it offers a commanding road presence without feeling bulky. LED headlights with signature daytime running lights provide excellent visibility, while the bold grille and chrome accents add visual drama.

• Aerodynamic efficiency: Low drag coefficient aids fuel economy and high-speed stability.
• Wheel options: From 18-inch alloys on base models to 20-inch AMG wheels on performance variants.
• Paint and trim: Extensive color palette, including metallic finishes like Selenite Grey.

Practicality is enhanced by frameless doors and flush handles, contributing to its modern aesthetic. However, the sloping roof impacts rear headroom, a trade-off for style enthusiasts.

Interior Comfort and Technology

Step inside the CLS Mk3, and you’re greeted by a cabin rivaling Mercedes’ top S-Class. High-quality leather, wood veneers, and aluminum trim create a sophisticated ambiance. Dual 12.3-inch displays form the MBUX infotainment system, controlled via touchscreen or voice commands with ‘Hey Mercedes’ activation.

Front seats offer excellent support with heating standard and ventilation available. Rear space suits adults for short trips, bolstered by ample legroom. Boot capacity is 520 liters, expandable via folding seats, though the high load lip requires care.

Engine Lineup and Performance

Power comes from efficient inline-six and V8 units, all paired with a smooth 9-speed automatic and rear- or all-wheel drive (4MATIC).

• CLS 300/350: 2.0L turbo petrol (258hp) or 3.0L mild-hybrid (299hp), 0-60mph in 6.0 seconds, up to 40mpg combined.
• CLS 450: 3.0L 6-cyl petrol-electric (367hp), 4.6s to 60mph, refined for long hauls.
• CLS 53 AMG: 3.0L 6-cyl hybrid (429hp), 4.5s sprint, top speed 155mph limited.
• CLS 63 S AMG: 4.0L twin-turbo V8 (603hp), 3.4s 0-60mph, ferocious yet composed.

AMG models shine with adaptive suspension, precise steering, and launch control. Standard CLS variants prioritize comfort, gliding over imperfections while delivering brisk pace.

Driving Experience: Balance of Thrill and Serenity

On highways, the CLS excels as a cruiser, with air suspension (optional on some) absorbing bumps seamlessly. Sound insulation mutes wind and tire noise, creating a library-quiet environment. Sport modes sharpen throttle and shift responses, revealing agile handling despite the 1,900kg weight. Brakes are strong and progressive, with AMG versions offering carbon-ceramics.

Track testing shows capable grip (0.91g skidpad), though it’s no pure sports car—understeer creeps in at limits. Everyday usability impresses: effortless overtaking, stable crosswinds, and intuitive aids reduce fatigue.

Safety Ratings and Driver Aids

Euro NCAP awarded five stars, praising structural integrity and active systems. Standard kit includes autonomous emergency braking, blind-spot monitoring, and traffic sign recognition. Higher trims add evasive steering assist and night vision.

• Adult occupant: 96%
• Child occupant: 91%
• Pedestrian: 78%
• Safety assist: 82%

These features make it one of the safest in class, ideal for families despite the coupe styling.

Reliability and Maintenance Insights

Mercedes reliability has improved, but the CLS demands diligent servicing. Intervals are 15,000 miles or yearly, with major checks at 77,500 miles for the gearbox. Common issues include electronics glitches and turbo wear on high-mileage AMG units.

Owners report high satisfaction with fit, audio, and dynamics. Warranty extensions are wise for used buys; check service history meticulously.

Ownership Costs: Premium but Justified?

Expect £40,000-£80,000 used prices, varying by spec and mileage. Fuel for V8s averages 20-25mpg; diesels (early models) better at 45mpg. Insurance groups 40-50, road tax £600+/year. Tyres cost £250 each, services £500+.

Resale holds strong for low-mileage examples.

What to Look for When Buying Used

Inspect for accident damage via paint thickness gauge. Verify full Mercedes history, especially oil changes and brake fluid (every 2 years). Test electronics, suspension for noises, and exhaust for leaks. AMG models: check supercharger whine and diff oil.

• Prioritize cars under 50,000 miles.
• Haggle on high-spec with few options.
• Professional PPI recommended.

Pros and Cons at a Glance

CLS Mk3 vs Rivals

Against Porsche Panamera (sportier but pricier), BMW 8 Series Gran Coupe (sharper handling), or Audi A7 (similar tech), the CLS wins on style and ease.

Frequently Asked Questions (FAQs)

Is the used Mercedes CLS Mk3 reliable?

With proper maintenance, yes—focus on service records to avoid costly repairs.

What’s the best engine for used CLS?

The 450 balances power, economy, and reliability for most buyers.

How practical is the CLS for families?

Suitable for two adults rear, with decent boot; not ideal for frequent five-seaters.

AMG versions worth the premium?

If you crave 600hp thrills, absolutely; otherwise, standard models suffice.

Fuel economy on AMG CLS63?

Real-world 20-22mpg combined, thirstier in sport mode.

The CLS Mk3 delivers unmatched luxury and poise, proving its worth for those who can afford it. Its blend of safety, tech, and performance ensures enduring appeal.