KNOWN FAULTS · Mercedes-Benz

Mercedes-Benz GLC (X253) GLC 200 / 250 / 300 (M274/M264) common problems.

2015–2022 · Petrol

Sources are not verified in real time and no entry confirms that your car is affected.

3 known faults with sources

M270/M274 chain, adjusters and thermostatTiming / leaks

Engine / equipment: M270 and M274 1.6/2.0 turbo petrol (A, B, CLA, GLA, C, E, GLC, SLC)
Period mentioned: 2012–2020
Symptoms: Chain rattle on cold starts; engine light with camshaft timing codes (for example P0016 or P001685); oil leaks at the camshaft adjusters; slow coolant loss.
Possible cause described: The hydraulic tensioner loses pressure overnight and the plastic guides wear, especially with long oil change intervals. The camshaft adjuster magnets leak oil (common between 65,000 and 110,000 km) and the plastic thermostat housing cracks.
Check for the garage: Listen to a cold start, read camshaft codes, look for oil on the adjuster magnets and coolant residue at the thermostat. Use Mercedes 229.5 oil.
Cost cited in the source: Chain and tensioner: approx. €320–1,650 (converted from dollars)A rough figure from the original database, not an up-to-date quote.

Mileage cited in the database: 65,000–110,000 km. This is not a maintenance interval and does not predict a failure.

Applies if: Only if fitted with the automatic gearbox described in the record.

9G-Tronic harsh shiftingAutomatic gearbox

Engine / equipment: 9G-Tronic automatic gearbox (725.0 and 725.1): C-Class W205 and W206, E W212 and W213, CLS, S W222 and W223, GLC, GLE, GLS, SL and SLC
Period mentioned: 2013–2026
Symptoms: Harsh or jerky shifts (especially 1st to 2nd and when cold), vibration, delayed shifts or limp mode; sometimes the gear will not engage from N to D. Codes P073E00 and P07B700.
Possible cause described: Mercedes acknowledges in a technical bulletin complaints of harsh shifts, shudder and limp mode with various causes. In the early years (2014–2016) it is usually software or adaptation rather than mechanical damage; in other cases the pressure sensor built into the gearbox control unit fails.
Check for the garage: Follow the Mercedes bulletin: reproduce the complaint, save the EEPROM, check the oil level, run the Xentry valve flush, update engine, gearbox and shift unit software and perform the standstill adaptation. If it persists, check the control unit.
Cost cited in the source: Software update and adaptation: the most common and cheapest fix; repairing or replacing the control unit costs considerably more (the sources give no comparable figures)A rough figure from the original database, not an up-to-date quote.

Applies if: Only with the M264 engine (not the M274).

M264 yellow coolant warning from air in the low-temperature circuit of the gearbox coolerCooling

Engine / equipment: M264 2.0 petrol in the C-Class (W205), E-Class (W213) and GLC (X253)
Period mentioned: 2024 technical note
Symptoms: Yellow coolant warning on the dashboard, with codes P0A0500, P00B700 or P0C7300 (low-temperature circuit circulation pump, or coolant flow too low).
Possible cause described: Air can be trapped in the cooling circuit of the gearbox cooler. It is described in Mercedes-Benz XENTRY technical note LI20.00-P-074205.
Check for the garage: Check the coolant level with the engine cold. If it is low, the leak must be found. If it is correct, the garage bleeds the gearbox cooler circuit at the point the brand gives (ideally filling the system under vacuum) and clears the codes.
Cost cited in the source: No verified estimate; ask the garage for a quote.A rough figure from the original database, not an up-to-date quote.