What is it?
Mercedes has given its whole GLC compact SUV line-up a mid-life makeover in an effort to keep it competitive in an increasingly crowded market sector. The 220d is expected to be the big seller when it comes on stream later this year, so until then, the 300d is the diesel-engined entry point and effectively replaces both the old 250d and 350d.
You’ll be hard pressed to spot the changes from the outside, so subtle are the upgrades. However, look closely and you might pick out the slimmer LED headlamps, reprofiled grille and subtly tweaked tail-lights. There are also restyled bumpers front and rear. It’s very subtle, but it does just enough to mark this out as the newer car.
It’s inside where some of the biggest changes have been wrought, with the GLC finally getting the latest electronic architecture already seen on the A-Class. All models get the MBUX 10.3in infotainment touchscreen with ‘Hey Mercedes’ voice command and a large central touchpad, which looks sleeker but is less intuitive than the old Comand rotary dial.
Ahead of the driver are standard analogue dials that flank a 5.5in trip computer screen, while AMG Line Premium models and above get a fully configurable 12.3in digital dial pack. This can also be ordered as an option on lesser versions. Finally, there’s Mercedes' latest steering wheel, which feels great in your hands but is festooned with buttons.
The mechanical changes are modest, although the 300d gets a more powerful version of the OM654 2.0-litre four-cylinder diesel engine already used in the A-Class and E-Class. With 241bhp and a very useful 369lb ft of torque, it’s nearly as powerful as the old 350d but produces the same twist as the 250d. As with all GLC models, it now comes as standard with the firm’s 9G-Tronic+ nine-speed automatic gearbox.
Standard cars get coil springs and adaptive dampers, with AMG Line versions getting a subtly stiffer set-up. Optional, and fitted to all of our test cars, is the Air Body Control three-chamber air suspension. All of this has been seen before; what’s new is the stability control system, which is now calibrated for every on and off-road driving mode, whereas before you simply had a choice of having it on or off.