Most common 2003 Mercedes-Benz C320 problems
Share of the 22 complaints; one complaint can involve more than one system. "~" is the median mileage when the problem started.
Mercedes-Benz C320 complaints by model year
Best C320 years: 2004, 2005, 2003. Years to avoid: 2002, 2001. Compare all years →
2003 Mercedes-Benz C320 recalls (3)
Visibility › Sun/moon roof assembly
Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2001-2011 C-Class, CLK, E-Class, and CLS vehicles. Please see the recall report for a complete list of models and model years. The glass sunroof panel may not be properly secured and can detach.
Remedy: Dealers will inspect and replace the sunroof panel as necessary, free of charge. Owner notification letters were mailed January 10, 2025. Owners may contact MBUSA customer service at 1-800-367-6372.
Visibility › Sun/moon roof assembly
Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2001-2011 C-Class, CLK, E-Class, and CLS vehicles. Please refer to MBUSA's recall report for specific vehicle model details. The glass sunroof panel may not be properly secured and may detach.
Remedy: Dealers will inspect and replace the sunroof panel as necessary free of charge. Owner notification letters were mailed February 3, 2023. Owners may contact MBUSA customer service at 1-800-367-6372.
Visibility › Sun/moon roof assembly
Mercedes-Benz USA, LLC. (MBUSA) is recalling certain 2001-2011 vehicles. The bonding between the glass panel and the sliding roof frame may deteriorate, possibly resulting in the glass panel detaching from the vehicle. For a full list of the affected models visit: https://static.nhtsa.gov/odi/rcl/2019/RMISC-19V918-4126.pdf
Remedy: MBUSA will notify owners, and dealers will inspect the glass panel bonding and replace the sliding roof, as necessary, free of charge. The recall began July 10, 2020.
What 2003 Mercedes-Benz C320 owners say
Electrical system
The contact owns a 2003 Mercedes-Benz C320. The contact stated that the sunroof had failed to open, and the sunshade cover failed to close, causing the sunrays to penetrate the vehicle. The vehicle was taken to the dealer, where an unknown assessment was made. The vehicle was not repaired. Additionally, the contact stated that the horn was inoperable. The SRS warning light was illuminated. The vehicle was taken to an independent mechanic, where it was diagnosed with front driver's side air bag failure. The vehicle was not repaired. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 124,000.
The secondary instrument fuse block located on the driver's side of the dashboard erupted in flame while the vehicle was being driven, endangering its occupant, causing significant damage to its interior, and resulting in a local law enforcement "traffic hazard" determination.
Transmission & drivetrain
"check coolant level" level warning sign was on. Apparently, there is leaking of coolant some where. It was at the water pump, which was replaced on June 20, 2019. It happens again now, about 9 months later.
On a 2003 c 320 mbnz, the radiator now leaks into the transmission. This is going to require the radiator to be replaced and for the transmission to be flushed. This leaking radiator fluid could have already damaged the transmission, and if so, it will have to be replaced. This problem causes a lack of power and therefore a loss of acceleration. It happens without any warning, often leaving you vulnerable due to the loss of power, a potential accident waiting to happen.
Engine & cooling
"check coolant level" level warning sign was on. Apparently, there is leaking of coolant some where. It was at the water pump, which was replaced on June 20, 2019. It happens again now, about 9 months later.
This happened in my 2003 C320 at 54,000 miles. I initially noticed a light rubbing or grinding while accelerating, with light vibration. At the dealership I was told I would need a new torque converter, new radiator, and a fluid flush. The radiator fluid was mixing with the transmission fluid. After those repairs, my C320 was still shifting hard and the grinding noise was still there. It turns out the transmission was ruined as well. Two replacement transmissions were needed until it was ready to be picked up. I've been told that the mixed fluids are not uncommon in this model and yet mbusa has made very little effort to answer my questions.
2003 Mercedes-Benz C320 engines & fuel economy
| Engine | Transmission | Drive | MPG city / hwy / combined |
|---|---|---|---|
| 3.2L 6-cyl | 5-speed automatic | RWD | 18 / 24 / 20 |
| 3.2L 6-cyl | 6-speed manual | RWD | 15 / 23 / 18 |
EPA ratings. Class: Compact car.
Frequently asked questions
Is the 2003 Mercedes-Benz C320 a good car?
Based on 22 owner complaints filed with NHTSA, the 2003 C320 rates better than average: 43% fewer complaints than a typical year of the C320 at the same age. It is one of the best C320 years by this measure. Complaint counts don't account for sales volume or individual maintenance, so have any used car inspected before buying.
What is the most common problem with the 2003 Mercedes-Benz C320?
The electrical system — 7 complaints, 32% of all complaints for this model year, most often about wiring › interior/under dash. Next are the transmission & drivetrain (5) and engine & cooling (4).
How many recalls does the 2003 Mercedes-Benz C320 have?
There are 3 recalls for the 2003 Mercedes-Benz C320, the most recent from November 19, 2024 (sun/moon roof assembly). Recall repairs are free at any authorized dealer — check whether yours has been done with the VIN recall check.
What are the best and worst years of the Mercedes-Benz C320?
The best years by complaints, compared at the same age, are 2004, 2005 and 2003. Years to avoid or approach with caution: 2002 and 2001. See the full Mercedes-Benz C320 years comparison.
At what mileage do 2003 Mercedes-Benz C320 problems happen?
The median mileage reported in complaints is about 54,000 miles; 33% of problems with a recorded mileage started before 50,000 miles.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.