Fault File
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Mercedes GLC

All generations and engines together · 78,810 MOT tests in the 2025 data · typical mileage at age 7: 65k

First-time failure at age 7
16.0%
Across 14,958 tests. The average across all tracked models is 19.5%.
Rank at age 7
73 of 239
1 = lowest failure rate among the models tracked.
Typical mileage at age 7
65k miles
Check the mileage view below; low-mileage models can look better by age than they are.

Generation

Split by first-registration year. Cars registered in a changeover year can belong to either generation.

How this model wears

Mercedes GLCClass average, all tracked models

Known issues

Measured

Computed from DVSA MOT results, all of Great Britain, 2025. Nothing here is opinion.

What testers flag

Share of tests where each item was recorded. The dark tick is the class average across all tracked models; bars are scaled within each group.

Faults with the car itself

The rows that judge the model rather than its keeper. 48,694 tests in this band.

A suspension pin, bush or joint excessively worn
Advisory
9.9%class 6.7%
A suspension pin, bush or joint excessively worn
Fail
4.6%class 0.7%
Engine MIL illuminated indicating a malfunction
Fail
2.0%class 0.9%
A transmission shaft constant velocity joint boot missing or no longer prevents the ingress of dirt etc
Fail
1.8%class 0.6%
A spring or spring component fractured or seriously weakened
Fail
1.1%class 1.4%
A transmission shaft constant velocity joint boot severely deteriorated
Minor
1.1%class 0.6%

Wear, upkeep and luck

Tyres, pads and stone chips say more about how the car was driven and maintained than about how it was built.

Tyre tread depth not in accordance with the requirements
Advisory
29.8%class 22.9%
A brake lining or pad worn below 1.5mm
Advisory
10.7%class 8.7%
A tyre seriously damaged
Advisory
10.7%class 13.4%
Brake disc or drum excessively weakened, insecure or fractured
Advisory
8.7%class 10.1%
Brake disc or drum significantly and obviously worn
Advisory
6.7%class 3.4%
Child Seat fitted not allowing full inspection of adult belt
Advisory
3.4%class 2.2%
Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view
Minor
2.7%class 2.0%
Tyre tread depth not in accordance with the requirements
Fail
2.6%class 2.2%

Unconfirmed issues

Reported

Owner folklore from forums and the motoring press. Most of it never shows up in an MOT, which is why this section exists at all.

Front wheel "crabbing" and judder on full lock

Confirmed pattern

On early GLC and GLC Coupe models, roughly 2016-2019, the front wheels can judder and hop when turning tightly at low speed or reversing, worse in cold weather. Mercedes first blamed winter tyres, then offered a free switch to all-season rubber, and later fitted a revised steering knuckle to persistent cases. It can show up from new and doesn't reliably clear itself with a tyre change alone.

Reported from new, worse in cold weather · sources: Honest John (GLC), Honest John (GLC Coupe)

Air suspension sagging or failing outright

Partly in the MOT data

Cars fitted with the optional Airmatic system can develop a leak in the compressor, valve block or air springs, leaving one corner sitting low or the whole car refusing to rise off its bump stops. It tends to surface from around 60-80k miles, and a repair runs into four figures if a corner needs replacing outright. Suspension is the standout MOT fault category for this model in the measured data too, so the general pattern owners describe lines up with what actually turns up at test time, even if the exact failed part varies car to car.

Reported 60-80k miles, Airmatic cars · sources: Honest John, Mercedes GLC Owners Club, club.autodoc.co.uk forum reports

Diesel timing chain rattle and injector/fuel pump wear

Diesel only

The 2.1-litre diesel (220d/250d, the OM651 engine) fitted to early GLCs can develop a rattly timing chain on cold start as the tensioner and guides wear, and some cars suffer piezo injector or fuel pump failures that cause misfires or a sudden loss of power. Mercedes did recall a batch of early OM651 diesels over chain tensioner sealing-ring tolerances, though most of the chain and injector wear owners report falls outside that recall and is an out-of-warranty repair rather than a free fix. Left to fail rather than caught early, it's a four-figure repair.

Diesel-only fault, reported from around 60k miles · sources: Honest John, honestcarcheck.co.uk, manufacturer recall filings

9G-Tronic automatic hesitation and rough shifts

Emerging

Owners of early cars report the nine-speed automatic occasionally hunting for the right gear or shunting into first at low speed, particularly in stop-start traffic. There's no public recall or acknowledged manufacturer fix, so it sits as a recurring owner complaint rather than a confirmed fault. Where it's bad enough to need attention, a transmission fluid and filter service is usually tried before anyone talks about the mechatronic unit itself.

Reported on early cars, no fixed mileage pattern · sources: honestcarcheck.co.uk, MBWorld GLC (X253) forum

COMAND infotainment glitches and battery drain

Emerging

The COMAND system can freeze, reboot itself or drop Bluetooth/CarPlay pairing, and a number of owners report a flat battery after the car has sat for a few days, put down to modules failing to sleep properly. Neither is dangerous but both are a nuisance to live with, and the usual fix is a dealer software reflash rather than a hardware swap. There's no manufacturer bulletin owners point to, so treat it as a known irritation rather than something with an official cure.

Reported across model years · sources: Honest John, honestcarcheck.co.uk, MBWorld GLC (X253) forum

Viewing one? Ask this

Built from the two sections above.

At low speed, turn the steering to full lock and feel or listen for judder or the front wheels hopping. Judder at full lock on an early car points to the known crabbing/steering knuckle fault.
Check ride height at all four corners, especially on cars with optional Airmatic suspension. A corner sitting noticeably lower than the others means an air suspension leak.
Start a diesel from cold and listen before the revs settle. A rattly chain noise for the first few seconds suggests timing chain or tensioner wear.
Drive an automatic through stop-start traffic, pulling away repeatedly from a standstill. Hunting for gears or a shove into first gear matches the reported 9G-Tronic hesitation.
Pair a phone by Bluetooth or CarPlay and cycle through every COMAND menu. Freezes, reboots or a screen that won't wake are signs of the reported infotainment glitches.
Ask when the car last sat unused for more than a few days and whether it needed a jump start. A history of flat batteries points to the reported parasitic drain.
Read the full MOT history for repeat suspension advisories, not just the overall pass or fail. Suspension is the class-level signature fault for this model, so recurring advisories here matter more than elsewhere.

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