The Mercedes-Benz GLA has been one of the better-selling premium compact SUVs in Australia since 2014. Two distinct generations have been sold here: the X156 (2014–2020), which shared its platform and petrol engines with the W176 A-Class, and the H247 (2020–present), a ground-up redesign featuring the M260 2.0-litre turbo four-cylinder, MBUX infotainment, and an updated dual-clutch transmission. Both generations carry a premium badge tax in servicing costs, and the H247 has introduced fresh fault patterns — particularly around the M260 cylinder-head defect, the dual-clutch gearbox, and 12V battery-related electrical issues — that any buyer should understand before committing.
Dual-Clutch Transmission (7G-DCT and 8G-DCT)
X156 (2014–2020) — 7G-DCT
The seven-speed dual-clutch paired to the M270/M274 petrol engines is prone to jerking and hesitation at low speeds, especially when cold. Owners commonly report clunks shifting from 2nd to 1st during deceleration and a brief roll-back on inclines as the clutches bite. A 2016 Australian recall (PRA 2016/15529) covered a welded seam in the dual-clutch assembly that could fracture and cause a sudden loss of drive; confirm this has been completed on any X156 sold between November 2015 and January 2016.
The 7G-DCT is not a lifetime-fill unit despite Mercedes' claims — specialists recommend a fluid service every 60,000 km. A dealer adaptation reset can improve shift quality ($300–$500). Clutch pack replacement requires removing the front subframe and is a substantial job ($2,500–$5,000+ in labour).
H247 (2020–present) — 8G-DCT
The eight-speed DCT in the H247 retains similar low-speed traits: hesitation from standstill, a clunk between drive and reverse, and jerky stop-start behaviour. These are most pronounced when cold and can improve significantly with a fluid change and transmission adaptation reset ($300–$600 at an independent Mercedes specialist). Severe shuddering or failure to engage warrants clutch pack inspection.
M260 Engine — Valve Seat and Cylinder-Head Defect (H247, 2020–2022)
This is the most serious documented fault on the H247. Mercedes-Benz has acknowledged that M260 engines produced approximately 2019–2022 can suffer premature wear of the exhaust valve seat rings and valve guides. As valve seats wear, the combustion chamber loses its seal, causing rough running, misfires (fault codes P0300/P0302 or similar), and reduced power. Symptoms typically appear between 30,000 and 80,000 km. The valve seats cannot be reworked — the entire cylinder head must be replaced.
Mercedes extended the cylinder-head warranty on affected M260 engines to 15 years or 241,000 km for 2019–2022 GLA, A-Class, CLA, and GLB models. When buying a 2020–2022 GLA, check whether the head has already been replaced under warranty, or confirm the car is still within that coverage window. The same defect affects the A-Class, CLA, and GLB on this platform.
M260 Timing Chain and Intake Carbon (H247)
Separately, the M260's timing chain tensioner can produce a brief cold-start rattle. If the rattle clears within a couple of seconds it is borderline; if it persists or is accompanied by misfires, have the chain and tensioner inspected. Carbon build-up on the intake valves (a common trait of direct-injection engines) typically becomes noticeable above 80,000–100,000 km as a rough idle. Walnut-blast cleaning of the intake valves costs roughly $400–$800 at a specialist.
M270/M274 Engine — Timing Chain and Carbon (X156 Petrol)
The GLA 200 (M270 1.6T) and GLA 250 (M274 2.0T) in the X156 share the same core fault: timing chain stretch from around 80,000–100,000 km, announced by a cold-start rattle. The system uses both upper and lower chains, which must be replaced together. Ignored, a stretched chain can jump a tooth and cause serious engine damage. A full timing kit replacement (chain, tensioner, guides, and often the camshaft actuator solenoids) runs $1,500–$3,000+ at an independent specialist. Walnut blasting of the intake valves is also recommended above 80,000 km if not already in the service history.
Electrical, MBUX, and 12V Battery (H247)
The H247's MBUX system routes almost all vehicle controls — including climate — through the central touchscreen. When it misbehaves, it is more disruptive than a conventional infotainment fault. Common complaints include screen blackouts, frozen displays, and spontaneous reboots. A weak 12V auxiliary battery (located in the boot) is the root cause far more often than a genuine MBUX hardware failure; the H247 draws continuously from it, and the car can go flat if left sitting for more than a week or two. Battery voltage should read 12.4V or above at rest; a replacement AGM 12V battery runs $200–$400 fitted.
Some owners also report the reversing camera showing a blank screen — often caused by corroded connectors at the tailgate passage rather than camera failure — and condensation pooling inside the tail-light housings.
Recalls and Safety
Both GLA generations have accumulated Australian safety recalls. The X156 was subject to multiple airbag recalls over its production life — including a window curtain airbag manufacturing variance, a passenger airbag propellant ratio issue, and an electrostatic discharge risk causing unintended driver airbag deployment — as well as the DCT weld-seam recall noted above. The X156 also falls within the national compulsory Takata airbag recall program; the ACCC pursued Mercedes-Benz formally over compliance pace, so verify any pre-2020 GLA is clear of outstanding Takata remedy work before buying.
Carify has recall data mapped for the 2020 model year. Check the 2020 GLA recall page for specifics, and see the car problems and recalls hub for the broader picture across all models.
Buying a Used Mercedes-Benz GLA? What to Check
- Cold-start the engine and listen for timing chain rattle (both generations). A tick that clears in one to two seconds is marginal; anything longer needs investigation.
- Verify the M260 cylinder-head status (H247 2020–2022). Look for a service record of the head being replaced under warranty, or confirm coverage remains in the 15-year/241,000 km window.
- Test the DCT in stop-start traffic. Some low-speed hesitation is characteristic; severe shuddering, delayed engagement, or clunking from park to drive should prompt a specialist check.
- Check the 12V battery voltage (H247). Below 12.2V at rest is a red flag and may explain any MBUX faults the seller attributes to software.
- Confirm all recalls are cleared — particularly the Takata airbag on X156 models and the 2016 DCT weld-seam recall. A VIN check or PPSR check will also surface finance encumbrances, write-offs, or stolen-vehicle flags before you commit.
- Prioritise full service history. Both the DCT and the M260 are sensitive to oil-change intervals; a documented dealer or specialist history is worth paying a small premium for.
The Verdict
The GLA is a genuinely well-engineered premium compact SUV with a strong footprint in the Australian used market. But it rewards buyers who do their homework: the DCT needs proper servicing and realistic low-speed expectations; the M260 valve-seat defect on 2020–2022 H247s is significant but manageable given Mercedes' extended warranty; and MBUX electrical dramas usually trace back to something as simple as a tired 12V battery. Buy one with a clean service record, verify all recalls are closed, and get a pre-purchase inspection from a Mercedes specialist. A Carify history report is a sensible first step before the inspection stage.