Mercedes-Benz GLS-Class, X166 (USA / CAN)

Brake fluid capacity & service interval

Mercedes-Benz GLS-Class, X166 (USA / CAN) requires 0,8 liter of brake fluid. The service interval for the fluid change is 24 months. The data covers 6 configurations.

The configuration chart below lists fill volumes and service intervals for each engine and trim variant.

TypeSpecifications
  • GLS 350 d 4MATIC, 166.823/824 (2017-2019)
  • ABS
  • Use: Normal
  • Capacity 0,8 liter
  • Change 24 months
  • GLS 450 4MATIC, 166.864 (2017-2019)
  • ABS
  • Use: Normal
  • Capacity 0,8 liter
  • Change 24 months
  • GLS 350 d 4MATIC, 166.823/824 (2015-2017)
  • ABS
  • Use: Normal
  • Capacity 0,8 liter
  • Change 24 months
  • GLS 450 4MATIC, 166.864 (2015-2017)
  • ABS
  • Use: Normal
  • Capacity 0,8 liter
  • Change 24 months
  • GLS 550 4MATIC, 166.873 (2015-2017)
  • ABS
  • Use: Normal
  • Capacity 0,8 liter
  • Change 24 months
  • GLS 63 AMG 4MATIC, 166.875 (2015-2019)
  • ABS
  • Use: Normal
  • Capacity 0,8 liter
  • Change 24 months

Additional Notes

  • Across all listed Mercedes-Benz GLS-Class X166 configurations — the GLS 350 d 4MATIC, GLS 450 4MATIC, GLS 550 4MATIC, and GLS 63 AMG 4MATIC — the brake fluid system capacity is uniformly specified at 0.8 liter. In hydraulic brake systems, this figure represents the total fluid volume held within the reservoir, master cylinder, brake lines, and ABS modulator combined.
  • The 24-month change interval applies under normal use conditions across all listed variants. A time-based interval of this kind reflects the hygroscopic nature of brake fluid, which absorbs moisture from the atmosphere over time and lowers the fluid's boiling point regardless of mileage accumulated.
  • All rows specify the hydraulic brake system with ABS as the applicable subsystem. ABS modulators add internal valving and fluid passages to the brake circuit, which is consistent with a system capacity in the 0.8-liter range rather than the smaller volumes seen in simpler non-ABS hydraulic circuits.
  • The GLS 350 d 4MATIC (166.823/824) and GLS 450 4MATIC (166.864) each appear across two overlapping year bands — 2015-2017 and 2017-2019 — with identical capacity and interval specifications in both entries. The 0.8-liter capacity and 24-month change interval remain unchanged between the two production periods for each of those variants.
  • The GLS 63 AMG 4MATIC (166.875) covers the full 2015-2019 span in a single entry, with the same 0.8-liter capacity and 24-month interval as the other variants. Despite the AMG designation, which typically involves a higher-performance braking setup, the total system fluid capacity does not differ from the non-AMG configurations listed.

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