Used Mercedes C-Class saloon review: 2014-2021 (Mk4) - Running costs, MPG, CO2 emissions and insurance

High servicing and insurance costs are on the debit side of C-Class Mk4 ownership, but at least the engines are economical

Carbuyer Rating

3.7 out of 5

Running costs, MPG, CO2 emissions and insurance Rating

3.5 out of 5

If you’re lucky and looking at a younger C-Class Mk4, there’s a chance that the original owner will have shelled out for a five-year service plan, and that it will be transferred to you with the sale of the car. That could save you a lot of money. 

Servicing costs for a C-Class Mk4 are high if you use a Mercedes dealer. You can spread the cost of two services by paying £40 a month for two years, but that equates to £480 per service, and one of those (the ‘A’ service) isn’t much more than an oil and filter change. Cars more than seven years old are eligible for a ‘value service’, which reduces the price of a ‘B’ service (oil change, new oil and pollen filters, topping up the AdBlue additive for diesel cars, and a general vehicle health inspection) to £305. At a city-based independent Mercedes specialist, however, an ‘A’ service costs between £150 and £175, and a ‘B’ service £230 to £250. So do shop around.

Also factor into your financial planning the fact that with the earliest versions of the C-Class Mk4 now being more than seven years old, wear-and-tear items such as tyres, exhaust systems, brakes discs and clutches may need replacing.

On the plus side, most of the C-Class Mk4’s engines are reasonably economical, with the diesel models returning between 58mpg and 69mpg, and the petrols ranging from 41mpg to 47mpg

How much do Mercedes C-Class Mk4s cost?

You won’t be stuck for choice when looking for a used C-Class Mk4, but most of them are for sale on secondhand car dealers’ forecourts rather than privately. Currently the dealers are trying to keep the price of just about any C-Class Mk4 above £15,000, even cars with 70-80,000 miles on the clock. Cheaper examples tend to have done closer to 100,000 miles, or more. 

Low mileage (30-40,000) cars from 2017 and 2018 can be priced in excess of £20,000, while those from 2019 and 2020 come in at over £25,000.

Used car prices do fluctuate, however, so the best way to keep abreast of what the market is doing right now is to visit our sister site, Buyacar, where you can access its special valuation tool.

What’s it like for fuel economy, emissions and tax?

Read through a fuel consumption comparison table and the clear winners for economy are the petrol-electric and diesel-electric plug-in hybrids, the C350e and C300de respectively. The petrol version has an official Combined figure of up to 134.5mpg and the diesel an astonishing 201.8mpg. Sounds too good to be true? They are. At least, in the real world. To achieve those figures the cars’ batteries need to be charged frequently, meaning you make the most of the 30-odd miles of electric running. However, if you use your car for a shortish commute or local hops, with only the occasional long run, then 100mpg should be easily achievable.

The turbodiesel C300 BlueTEC Hybrid (a non-plug-in mild hybrid with a small electric motor working alongside the conventional engine to boost performance and fuel economy, and reduce CO2 emissions) is claimed to give up to 78.5mpg, but this is using the old NEDC method of testing economy – expect that figure to fall by at least 10mpg if the car was tested under the newer WTLP regime, said to better represent real world driving.

Some models of the 158bhp 1.6-litre turbodiesel C200d are claimed to travel up to 72.4 miles on a gallon, while the high performance 242bhp C300d posts an impressive 57.7mpg. Most of the other diesels are in the high 50mpg to mid 60mpg range. Fuel consumption figures start at just over the 40mpg mark for the petrol-engined C-Class Mk4s, and span to 53.3mpg for certain versions of C200. It’s worth noting that cars fitted with Mercedes’ 4Matic four-wheel drive system suffer roughly an 8mpg fuel consumption penalty.

Unsurprisingly the plug-in hybrid models have the lowest official CO2 emissions, 38-42g/km for the diesel version and 48-52g/km for the petrol. The mild hybrid turbodiesel C300 BlueTEC Hybrid is just 95g/km, while the C200 1.5-litre turbocharged petrol mild hybrid is way adrift at 140g/km.

Of the rest of the diesels the 1.6-litre C200d shines for emitting between 101g/km and 113g/km depending on the model, although the more powerful C250d impressively achieves 110g/km in its most efficient form. The thirstier petrol models emit more CO2, but the 254bhp C300’s best of 136g/km looks good in the context of the 134g/km best of the 154bhp 1.6-litre C180.

Cars first registered before 1 April 2017 are taxed according to their CO2 emissions, which means that the plug-in hybrids are tax-exempt, while several of the low-emissions diesel models are between £20 and £30 annually. Depending on trim grade, however, that cost can rise to £120-130. Some petrol models can be as much as £210.

For cars registered after 1 April 2017 there’s a flat rate of road tax that for most versions of the C-Class is £155, although some of the more frugal models cost £130. However, if your C-Class Mk4 cost more than £40,000 when new, there’s also a luxury car surcharge that pushes up the road tax total for the first five years after registration to between £480 and £490 annually, even for the plug-in hybrid models.

How much does the Mercedes C-Class Mk4 cost to insure?

From an insurance company’s perspective, premium brand cars such as Mercedes cost a lot to replace and repair, which is why they’re placed in high insurance groups. The mainstream versions of the C-Class Mk4 sit in groups 30 to 44 out of 50.

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