Generation Overview
| Generation | Years | Key Engines (US) | Reliability Profile |
|---|---|---|---|
| ML W164 | 2006–2011 | 3.5 V6 M272, 5.5 V8 M273, 6.3 AMG | AIRMATIC failure-prone; balance shaft on M272/M273; avoid unless priced accordingly |
| ML W166 | 2012–2015 | 3.5 V6 M276, 4.6 V8 M278, 5.5 V8 AMG | Significant improvement; AIRMATIC still needs service planning; M276 balance shaft window |
| GLE W166 | 2016–2019 | 3.0T V6 M276, 4.7 V8 M278, 5.5 V8 AMG | Carryover platform with refinements; last generation before full redesign |
| GLE W167 | 2020+ | 2.0T I4, 3.0T I6 EQ Boost, 4.0T V8 AMG | New MHA platform; most reliable GLE generation; significantly less AIRMATIC drama |
ML W164 (2006–2011): The Difficult Generation
The W164 ML-Class is the generation that gave the ML nameplate its reliability reputation — and it earned it. The combination of AIRMATIC air suspension, M272/M273 balance shaft exposure, and early 7G-Tronic conductor plate susceptibility means a high-mileage W164 has likely encountered at least two of these failure points. At the prices W164s now trade for, they can still make sense — but only if you go in with eyes open and a realistic repair budget.
W164 AIRMATIC: Near-Certain Failure by 100K
AIRMATIC was standard on most US W164 trims. By 100,000 miles, air strut failure is statistically near-certain on an unserviced W164. The failure sequence is consistent: one rear strut develops a slow leak, the compressor runs overtime to compensate, the compressor fails, and suddenly the car is sitting on the bump stops. The full repair process is documented in the AIRMATIC failure guide. For W164 buyers, build $2,000–$4,000 of AIRMATIC budget into your purchase calculation unless you can confirm recent strut replacement.
W164 Balance Shaft on M272/M273
ML350s with the M272 V6 (2006–2011) and ML550s with the M273 V8 (2007–2011) both fall within the balance shaft failure window. See the balance shaft guide for production-date VIN identification. An ML-Class with the M272 or M273 that hasn't been inspected for balance shaft wear is a known-unknown in your purchase.
ML W166 (2012–2015) and GLE W166 (2016–2019): The Better Platform
The W166 generation is a significant improvement over the W164 in every dimension. The AIRMATIC system is more reliable but not immune — air struts on high-mileage W166s still fail, just less frequently and at higher mileage. The M276 V6 used in the ML350 and GLE350 shares balance shaft design concerns with earlier M272/M273 engines in early production; updated later in the M276 production run. The M278 biturbo V8 in ML550 and GLE550 models does not share this concern.
The W166/GLE166 is the sweet spot of the used ML/GLE market for buyers who want a capable SUV at a reasonable price point. A well-maintained W166 ML350 or GLE350 with documented service history is a very good used buy in the $20,000–$32,000 range. The key verification items: AIRMATIC strut condition, 7G or 9G-Tronic service history, and M276 VIN-based production date check.
GLE W167 (2020+): The Redesigned Generation
The W167 GLE on the new MHA platform is the most capable and most reliable GLE Mercedes has produced. The 2.0T four-cylinder in the GLE300d (diesel, not US-spec) and the 3.0T inline-six EQ Boost in the GLE450 and GLE580 are modern engines with a different service profile than previous V6/V8 offerings. The 48V EQ Boost mild-hybrid system smooths low-speed operation and reduces belt-starter-generator wear compared to conventional alternator-starter arrangements.
W167 service priorities: 9G-Tronic fluid at 40,000 miles, spark plugs at 60,000 miles on the 2.0T (55,000 on the inline-six), brake fluid every two years, and transfer case fluid at 60,000 miles. The AIRMATIC system on the W167 has shown better durability in early data — strut failures before 100,000 miles are less common than on W164/W166 cars.
GLE63 AMG Notes (All Generations)
The AMG versions across all generations command a premium at purchase but have specific service requirements that increase the ownership cost calculation. The M157 biturbo V8 in W164/W166 AMG models has a documented camshaft adjuster wear pattern at higher mileage. The current M177 4.0T V8 in the W167 GLE63 is a very capable engine — keep oil changes at 5,000-mile intervals with 229.51 spec oil and it will last. AMG models across all GLE generations have larger brake setups that wear faster and cost significantly more per axle to service than standard trims.