Where each one leads
Kia Optima
- Fewer Kia Optima cars in the Netherlands carry an illogical odometer record (3.9% against 4.5%).
Mercedes-Benz C-Class
- Against cars of the same year, the Mercedes-Benz C-Class comes out better in New York safety inspections (fails 38% less often than average) than the Kia Optima (fails 43% more often than average).
- New Mercedes-Benz C-Class cars registered in Europe in 2022 average 116 g/km of CO₂ on the WLTP test, against 167 for the Kia Optima in 2022.
Too close to call: MOT pass rate against cars of the same age; NHTSA overall safety rating.
Only measures that do not depend on how many cars were sold: pass and failure rates against cars of the same age, ratings, fuel use and CO₂. How we compare
At a glance
| Kia Optima | Mercedes-Benz C-Class | |
|---|---|---|
| Model years in the US safety record | 2001–2020 | 1991–2012 |
| New cars registered in Europe | 70,043 (2011–2022) | 1,573,424 (2010–2022) |
| Licensed in the United Kingdom | 10,626 | 342,811 |
| On the road in the Netherlands | 1,338 | 78,492 |
| In traffic in Finland | 3,788 | 49,488 |
EEA new-car registrations (CC BY 4.0) · DVLA licensed vehicles (OGL v3.0) · RDW (CC0) · Traficom (CC BY 4.0) · generations: Wikidata (CC0).
Reliability and problems
| Kia Optima | Mercedes-Benz C-Class | |
|---|---|---|
| UK MOT first-time pass rate | 80% | 80% |
| … against cars of the same age | −1% | +1% |
| New York safety inspections failed | 2.9% | 1.1% |
| … against cars of the same year | +43% | −38% |
| Illogical odometer records (NL) | 3.9% | 4.5% |
| US owner complaints | 7,528 | 192 |
| Most complaints about | Engine | Electrical system |
| Model year with most complaints | 2013 (1,386) | 1995 (49) |
| US recall campaigns | 22 | 6 |
| Manufacturer service bulletins | 2,057 | 73 |
| NHTSA defect investigations | 62 | 11 |
Complaint, recall and bulletin counts grow with the number of cars sold and are not adjusted for it. UK MOT: DVSA anonymised MOT results (OGL v3.0); New York: DMV inspections; complaints, recalls, bulletins and investigations: NHTSA (public domain); odometer: RDW (CC0).
Safety
| Kia Optima | Mercedes-Benz C-Class | |
|---|---|---|
| NHTSA overall rating | 5★ (2020) | 5★ (2021) |
NHTSA New Car Assessment Program, most recent rated model year (public domain).
Fuel, emissions and price
| Kia Optima | Mercedes-Benz C-Class | |
|---|---|---|
| Official combined fuel use, Canada | 8.4 l/100 km (2020) | — |
| Real-world use in Europe, diesel hybrid | — | 6.0 l/100 km |
| Real-world use in Europe, petrol hybrid | — | 8.5 l/100 km |
| Real-world use in Europe, diesel | — | 6.3 l/100 km |
| Real-world use in Europe, petrol | — | 10.9 l/100 km |
| Official CO₂ of new cars in Europe | 167 g/km | 116 g/km |
| Average power of new cars in Europe | 173 kW (231 hp) | 152 kW (203 hp) |
| Average mass in running order | 1,626 kg | 1,818 kg |
| Dutch list price when new (median) | €41,790 | €54,166 |
| Average odometer in Finland | 149,000 km | 248,000 km |
Canada: NRCan Fuel Consumption Ratings, most frugal version of the latest year (OGL Canada). Europe: EEA monitoring of new-car CO₂ and on-board fuel meters (OBFCM), CC BY 4.0. Price: RDW catalogue price (CC0). Finland: Traficom (CC BY 4.0).