Is the 2021 Mercedes-Benz C 300 reliable?

The 2021 Mercedes-Benz C 300 has 15 complaints filed with NHTSA (0.4x the segment average). Our reliability verdict: excellent. Most common issue: ENGINE problems.

What are common problems with the 2021 Mercedes-Benz C 300?

Top problems: ENGINE (7 complaints, avg repair $500); FUEL SYSTEM (3 complaints, avg repair $500); AIR BAGS (1 complaints, avg repair $500). Issues typically appear around 50K miles.

Are there any recalls on the 2021 Mercedes-Benz C 300?

Yes, there are 5 recall(s): FUEL SYSTEM, GASOLINE:DELIVERY:FUEL PUMP, ELECTRICAL SYSTEM:SOFTWARE, ELECTRICAL SYSTEM:SOFTWARE, SEAT BELTS:FRONT:RETRACTOR, BACK OVER PREVENTION:DISPLAY FUNCTION. Contact any Mercedes-Benz dealer to verify if recalls have been completed on your specific vehicle.

How much does it cost to fuel a 2021 Mercedes-Benz C 300?

The 2021 Mercedes-Benz C 300 gets 27 MPG combined. At current US average gas prices, driving 12,000 miles per year costs roughly $1778. See the interactive fuel cost calculator on this page for state-specific pricing.

How much does it cost to insure a 2021 Mercedes-Benz C 300?

Estimated US average full-coverage insurance for the 2021 Mercedes-Benz C 300 is approximately $2,250/year (sedan-luxury class). Actual quotes vary heavily by state, driver age, driving record, and credit — see the interactive insurance estimator on this page for state-specific pricing.

2021 Mercedes-Benz C 300

Problems, Recalls & Reliability Report

Excellent Reliability

Quick Summary

The 2021 Mercedes-Benz C 300 has 15 owner complaints filed with NHTSA — that's 0.4x the segment average of 39. The most common issue is engine problems (47% of all complaints), specifically: piston connecting rod broke and left the engine making holes in both sides of the block; mercedes benz rejected any responsibility because the car has a branded title. currently a new engine (brand new) is being installed, my concern is that what will happen if the new engine has the same defective . There are 5 recalls issued for this model year.

Total Complaints

Recalls Issued

—/5

Safety Stars

0.4x

vs Segment Avg

Known Problems(top 5 of 7)

ENGINE

7 complaints

47%

• Piston Connecting Rod broke and left the engine making holes in both sides of the block; Mercedes Benz rejected any responsibility because the car has a branded title. Currently a new engine (brand new) is being installed, my concern is that what will happen if the new engine has the same defective
• First day leasing the vehicle within 6 hours lights malfunction and malfunction warning on dash to seek workshop, vehicle was taken for inspection to original dealer (Mercedes Benz of Bakersfield). During inspection I added additional concerning complaints about passenger door not closing correctly/
• the check Engine light fault code P012D12 The pressure sensor upstream of the turbocharger had a short circuit to positive. Found Kink wire on upstream pressure sensor. A short circuit to positive. Electrical Wire replaced.

Typical onset: 50K miles Est. repair: $500

“Piston Connecting Rod broke and left the engine making holes in both sides of the block; Mercedes Benz rejected any responsibility because the car has a branded title. Currently a new engine (brand new) is being installed, my concern is that what will happen if the new engine has the same defective ”

— NHTSA complaint filing

Recalls (5)

FUEL SYSTEM, GASOLINE:DELIVERY:FUEL PUMP26/06/2023

Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2021-2023 C-Class, E-Class, S-Class, CLS, SL, GT, GLC, GLE, GLS, and G-Class vehicles. Please refer to MBUSA's recall report for specific vehicle details. The fuel pump may shutdown, which can result in a loss of drive power.

Risk: A loss of drive power can increase the risk of a crash.

Fix: Dealers will replace the fuel pump, free of charge. Owner notification letters were mailed on June 14, 2024. Owners may contact MBUSA customer service at 1-800-367-6372. MBUSA's number for this recall is 2023070012.

Fuel Cost Calculator for 2021 Mercedes-Benz C 300

Live EIA prices

Annual miles driven: 12,000

Your state (affects local gasoline price)

Per year

$1,778

Per month

$148

Per mile

14.8¢

MPG

City driving (worst-case MPG)

$2,087/yr

Highway driving (best-case MPG)

$1,372/yr

Based on EPA fuel-economy ratings and EIA weekly retail prices (2026-07-20). Real-world cost varies with driving style, trim/engine, terrain, and traffic.

5-Year Gas Price History

EIA weekly retail data · 2021 → today

Show:

Current

$4.00

5-year low

$2.78

5-year high

$5.01

Since 2021

+27%

Source: US Energy Information Administration weekly retail gasoline prices.

Estimated Insurance Cost for 2021 Mercedes-Benz C 300

Estimate only, not a quote. Modeled from NAIC + HLDI averages for a hypothetical 35-year-old driver with clean record + full coverage. Your actual quote depends heavily on your age, driving history, credit, ZIP code, and insurer.

Your state (affects local premium average)

Full coverage / year

$2,250

Full coverage / month

$188

Liability only / year

$710

vs US avg

+34%

How this estimate is calculated

US base full-coverage premium$1674

× state (US)1.00x

× vehicle class (sedan-luxury)1.28x

× theft risk1.00x

× safety rating1.00x

× vehicle age1.05x

= Full coverage estimate$2250

Coverage assumed: 100/300/100 liability + comprehensive/collision, $500 deductibles. Data sources: NAIC 2024 + HLDI loss studies.

Maintenance & Warranty

Recommended Mercedes-Benz C 300 Service Intervals

Oil change

10K mi / 12 mo

Tire rotation

10K mi

Brake fluid

24 months

Transmission fluid

40K mi

Engine coolant

150K mi

Spark plugs

60K mi

Cabin air filter

20K mi

Engine air filter

40K mi

Differential (AWD/4WD)

40K mi

Service A / Service B alternating schedule. Requires MB-approved oil (229.5 spec typically).

"Severe service" conditions (heavy towing, extreme temps, city stop-and-go) typically halve these intervals. Always consult your vehicle's owner's manual for the authoritative schedule.

Mercedes-Benz New-Vehicle Warranty Coverage

Bumper-to-bumper (basic)

4 yr / 50K mi

Powertrain

4 yr / 50K mi

Hybrid/EV battery

10 yr / 155K mi

Corrosion (rust perforation)

4 yr / 50K mi

Roadside assistance

4 yr / unlimited mi

EQ EV battery warranty is 10 years/155,000 miles

These are the terms for a new Mercedes-Benz. If you're buying a used 2021 C 300, remaining coverage is usually pro-rated from the vehicle's original in-service date. Not all coverage transfers between owners — check with a Mercedes-Benz dealer for VIN-specific remaining warranty.

Estimated Repair Costs

ENGINE(~50K mi)

$500

FUEL SYSTEM(~50K mi)

$500

AIR BAGS(~50K mi)

$500

ELECTRICAL(~50K mi)

$500

DRIVER ASSIST/CAMERAS(~50K mi)

$500

Estimates based on average reported repair costs. Actual costs vary by location, shop, and severity.

🔍 Pre-Purchase Inspection Checklist

Based on 15 owner complaints for this specific year, here's what to check or ask about:

☐
ENGINE: Piston Connecting Rod broke and left the engine making holes in both sides of the block; Mercedes Benz rejected any responsibility because the car has a branded title. Currently a new engine (brand new) is being installed, my concern is that what will happen if the new engine has the same defective
Typically appears around 50K miles. Repair cost ~$500
☐
FUEL SYSTEM: While driving car on Sunday 10/5, it suddenly failed to respond to gas pedal pressure. The car stopped accelerating and rather slowed to 15 MPH, almost causing a car from behind to hit me in the rear side.
Typically appears around 50K miles. Repair cost ~$500
☐
AIR BAGS: The contact owns a 2021 Mercedes-Benz C300. The contact stated while driving at an unknown speed, there was a burning odor inside the vehicle. The contact stated the passenger side air bags was enabled warning light was illuminated. The contact also stated the vehicle made an abnormal noise. The con
Typically appears around 50K miles. Repair cost ~$500
☐
ELECTRICAL: First day leasing the vehicle within 6 hours lights malfunction and malfunction warning on dash to seek workshop, vehicle was taken for inspection to original dealer (Mercedes Benz of Bakersfield). During inspection I added additional concerning complaints about passenger door not closing correctly/
Typically appears around 50K miles. Repair cost ~$500
☐
RECALLS: Verify all 5 recalls have been completed — free at any Mercedes-Benz dealer
☐
General: Get a pre-purchase inspection from an independent mechanic ($100-$200)