In-depth reviews

Mercedes GLC review - MPG, CO2 and running costs

Standard nine-speed automatic gearbox keeps running costs down and on-par with rivals

As a mid-sized SUV, it shouldn’t come as much of a surprise that the GLC can’t quite match the fuel economy of the C-Class saloon.

Still, the engine improvements introduced for 2019 resulted in small improvements across the board. The latest GLC 220 d delivers between 44.8mpg and 45.6mpg on the WLTP combined cycle, dependent on chosen optional equipment.

The GLC 300 d is slightly thirstier, offering 42.2mpg to 42.8mpg. In terms of carbon dioxide emissions, the GLC 220 d manages 166g/km, while the 300 d achieves 172g/km. Both cars see a slight increase in emissions when larger wheels are fitted.

Plug-in diesel hybrid tech gives the GLC 300 de a 27-mile all-electric range and CO2 emissions from 49g/km, while Mercedes claims maximum fuel consumption on the combined cycle of 156.9mpg - although you'll have to ensure the battery is kept topped-up. The petrol-electric 300 e PHEV manages up to 128.4mpg and 52g/km.

The petrol GLC 300 returns up to 33.6mpg and has emissions from 194g/km. At the other end of the scale, the AMG GLC 63 S emits 295g/km and returns up to 22.1mpg, while the GLC 43 manages 246g/km and up to 25.5 mpg.

Servicing and maintenance costs should be on a par with a BMW and Audi, and the fact it shares a number of parts with the C-Class saloon should bring down costs in the long term.

Insurance groups

The insurance groups for the GLC generally range from around group 28 to group 38 for the standard models, depending on engine and trim level. The AMG GLC 43 has a group 40 insurance rating, while the AMG 63 models tops out in group 47. Insuring a premium car such as this could be a big chunk of your annual running costs, and when we tested the previous-gen GLC 250 d AMG Line against a Volvo XC60 D4 R-Design and Audi Q5 2.0 TDI S line, the GLC was the most expensive to insure: our sample driver was quoted at around £1,200, compared to around £850 for the Volvo and Audi.


Premium SUVs are a popular part of the market, and the GLC has reasonable residual values to reflect this. The conventional range sits in the ballpark of around 45%, which is in line with rivals. The GLC Coupe is a stronger performer in the used market, keeping around 50% of its original value over the same period. The AMG models do not hold up so well in percentage terms and, due to their high list prices, will lose the first owner a considerable chunk of money.

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