The Mercedes-Benz GLE450 (W167) arrived in Australia in 2019 as a complete redesign of the large luxury SUV, pairing a 3.0-litre turbocharged M256 inline-six petrol engine with a 48V EQ Boost mild-hybrid system. Standard equipment includes AIRMATIC air suspension, the 9G-TRONIC nine-speed automatic, and the MBUX dual-screen infotainment setup. It is an impressive vehicle, but it is also a complex machine with higher-than-average repair costs. Used examples have revealed a handful of repeating problems that buyers should investigate. The GLE450 is not uniquely unreliable for its class, but it rewards owners who understand its weak points and budget accordingly.
M256 engine: oil filter housing leaks
The M256 3.0-litre inline-six is a capable engine, but the oil filter housing adapter is a documented weak point. The adapter bolts to the side of the engine block and incorporates an oil cooler; its sealing gasket hardens with heat cycling and eventually allows oil to seep down onto hot exhaust components below. The first sign is usually a burning smell after a run, or a film of oil on the undertray.
- Symptoms: Oil drips under the front of the engine; burning smell from the engine bay; oil residue on the block near the filter housing.
- Affected vehicles: All GLE450 W167 models from 2019 onward; more common past 60,000–80,000 km.
- Typical fix and cost: Replacement of the housing adapter and gasket — roughly $600–$1,200 at an independent specialist.
Some owners also report a brief cold-start rattle lasting a second or two when the engine first fires in cool weather, caused by the timing chain tensioner taking a moment to build oil pressure. A rattle that persists beyond a few seconds, or worsens over time, warrants prompt inspection — timing chain tensioner replacement on the M256 is expensive if left too long.
48V EQ Boost system and wiring harness
The 48V mild-hybrid system — 48V lithium-ion battery, integrated starter-generator (ISG), and DC/DC converter — adds genuine performance benefits but introduces a category of electrical fault not found in conventional vehicles. Owners report "48V Battery Malfunction" or "Hybrid System Error" warnings in the instrument cluster, sometimes with reduced power or rough engine restart behaviour. Software updates from Mercedes-Benz resolve some false-positive warnings, but genuine hardware failures require component replacement at significant cost.
More critically, Australian recall REC-005948 (covering GLE and GLS vehicles from 2019–2022) found that the nut securing the 48V wiring harness under the driver's seat may have been fastened with insufficient torque at the factory, creating elevated resistance and a potential fire risk. The remedy is a dealer inspection and re-torquing at no charge. Check the 2019 GLE450 recall page on Carify to confirm whether this work is recorded for the car you are considering.
AIRMATIC air suspension faults
The AIRMATIC air suspension delivers a comfortable and adjustable ride, but has a well-documented failure pattern. The rubber bellows inside each air strut gradually crack or develop pinhole leaks, causing one or more corners of the car to sag — most noticeable after the car has sat overnight.
- Symptoms: One corner sitting lower than the others; "AIRMATIC Fault — Visit Workshop" message; hissing from the suspension when parked; compressor running continuously or noisily.
- Root cause: Leaking bellows force the air compressor to work overtime. A compressor running constantly will eventually burn out, turning a $800–$1,500 strut repair into a $2,500–$4,000 job.
- Fix: Individual air strut replacement. OEM Mercedes struts typically cost $1,200–$2,500 per corner for parts before labour; quality aftermarket alternatives are available at lower cost. An independent AIRMATIC specialist is usually more cost-effective than a franchised dealer.
Note that not all AIRMATIC fault messages mean a mechanical failure. A technical service bulletin for the W167 platform notes the warning can be triggered by a software fault in the AIRMATIC control unit, resolved by a dealer software update — so get fault codes read before authorising parts replacement.
9G-TRONIC transmission
The GLE450 is subject to Australian recall REC-005922 (covering model series 167, 2019–2023): a software fault in the transmission control module can cause the gearbox to fail to complete a downshift under certain conditions, resulting in a sudden loss of engine power. Mercedes-Benz Australia remedied this with a transmission software update at no charge — confirm it has been done before buying.
Beyond the recall, some 9G-TRONIC units develop hesitant or harsh shifts — particularly on low-speed Drive or Reverse engagement — as the car ages. Mercedes markets the ATF as a "lifetime" fill, but a fluid and filter service every 60,000–80,000 km significantly extends valve-body longevity. Budget roughly $400–$700 for a professional ATF service at an independent workshop.
MBUX infotainment and electrical issues
Early MBUX software versions had stability problems: screens freezing or going blank, systems rebooting mid-drive, Bluetooth dropping connections, and navigation becoming unresponsive. Mercedes-Benz has released multiple software updates that address most of these. An unserviced car running outdated MBUX software is more likely to exhibit them. A hard reset (holding Home and Back simultaneously for several seconds) resolves temporary freezes. Persistent hardware failures — which can require replacing the MBUX control unit under the passenger seat — can run $1,500–$3,500 in parts and labour.
Recalls & safety
The W167 GLE450 has accumulated several entries in the Australian Product Safety Recalls database (vehiclerecalls.gov.au). Verified recalls include:
- REC-000937 (2019 models): Air-conditioning drain hoses incorrectly installed — potential interior condensation, electrical short circuits, and fire risk.
- REC-005948 (2019–2022 models): 48V wiring harness nut under the driver's seat insufficiently torqued — fire risk.
- REC-005922 (2019–2023 model series 167): Transmission control module software fault causing potential engine stall.
Check the 2019 GLE450 recall page for year-specific details, and browse the Carify recalls landing page for the full picture across all models.
Buying a used Mercedes-Benz GLE450? What to check
A pre-purchase inspection by a Mercedes-Benz specialist is strongly recommended. Focus on these areas:
- Oil filter housing: Check the side of the M256 engine block for oil residue around the filter housing. Any sign of a developing leak should be factored into your offer.
- Cold start: Start the engine from cold and listen for timing chain rattle. A brief tick clearing in under two seconds is not unusual; anything longer needs investigation.
- 48V recall: Confirm REC-005948 has been completed at a Mercedes dealer. Check for any active "48V Battery Malfunction" warnings on the instrument cluster.
- Suspension: Leave the car parked briefly and confirm it sits level on all four corners. Drive over varied surfaces and listen for clunks, hissing, or uneven ride.
- Transmission: Confirm REC-005922 transmission software is updated. Check for hesitant engagement from Park and ask for records of any ATF service.
- Service history and VIN check: Full dealer history adds genuine reassurance. Run a PPSR check to confirm the car is clear of finance or write-off records before you sign anything.
The verdict
The Mercedes-Benz GLE450 W167 is a polished large luxury SUV that remains a credible used buy — provided buyers go in with clear eyes. The M256 engine is fundamentally sound but needs monitoring for oil filter housing leaks and cold-start rattle. The 48V EQ Boost system and AIRMATIC suspension are impressive in operation but costly when they fail. Three verified Australian recalls — one carrying a fire risk from the 48V harness — make recall confirmation essential. Buyers who insist on a complete service history, verified recall completions, and a specialist pre-purchase inspection will find the GLE450 a rewarding car to own. Those who skip these steps may be unpleasantly surprised by the first major repair bill.