2021 Mercedes-Benz Alliado

The 2021 Mercedes-Benz GLB 250 is a compact SUV offering a blend of luxury and practicality. Engine options include a 2.0-liter inline-4 turbocharged engine producing 221 horsepower and 258 lb-ft of torque. It is exclusively paired with an 8-speed dual-clutch automatic transmission. Owners often praise its spacious interior, comfortable ride, and upscale features. Some common complaints include the touch-sensitive controls being difficult to use and the sometimes rough shifting of the dual-clutch transmission.

Engine

2.0L Turbocharged Inline-4

• Coolant Leak from Thermostat Housing
  • Description/Symptoms: Coolant leak, often with a visible puddle under the vehicle. May also cause a coolant warning light.
  • Solution: Replacement of the thermostat housing.
  • Estimated Cost to Fix: $300 - $500+
  • Recalls: None Found
• Oil Leak from Valve Cover Gasket
  • Description/Symptoms: Oil leaking onto the exhaust manifold, causing a burning smell. Visible oil accumulation around the valve cover.
  • Solution: Replacement of the valve cover gasket.
  • Estimated Cost to Fix: $200 - $400+
  • Recalls: None Found
• Check Engine Light Due to Faulty Oxygen Sensor
  • Description/Symptoms: Illuminated check engine light, potential decrease in fuel economy, and possible rough idle. Diagnostic codes related to the oxygen sensor.
  • Solution: Replacement of the faulty oxygen sensor.
  • Estimated Cost to Fix: $200 - $400+
  • Recalls: None Found

Transmission

8-Speed Dual-Clutch Automatic Transmission

• Rough or Jerky Shifting
  • Description/Symptoms: Harsh or jerky shifting, especially during low-speed acceleration or deceleration. Hesitation when shifting gears.
  • Solution: Software update to the transmission control module (TCM). In some cases, transmission fluid service or replacement of the mechatronic unit.
  • Estimated Cost to Fix: Software update: $150-$300, Fluid Service: $300 - $500, Mechatronic unit: $2000+
  • Recalls: None Found
• Transmission Slippage
  • Description/Symptoms: Engine revving high without corresponding acceleration. The car feels like it’s not “catching” the gear properly.
  • Solution: Replacing the clutch packs or the entire transmission if the damage is extensive.
  • Estimated Cost to Fix: Clutch pack replacement: $1500 - $3000+, Transmission replacement: $6000+
  • Recalls: None Found

Suspension

• Premature Wear of Front Struts/Shocks
  • Description/Symptoms: Bouncy ride, excessive body roll during cornering, and clunking noises from the front suspension.
  • Solution: Replacement of the front struts/shocks.
  • Estimated Cost to Fix: $600 - $1200+
  • Recalls: None Found

Electrical

• Malfunctioning MBUX Infotainment System
  • Description/Symptoms: Freezing, lagging, or crashing of the MBUX infotainment system. Difficulty connecting to Bluetooth or using navigation.
  • Solution: Software update to the MBUX system. In some cases, replacement of the infotainment unit.
  • Estimated Cost to Fix: Software update: $0 - $200, Infotainment unit replacement: $1500 - $3000+
  • Recalls: None Found
• Sensor Failures (Parking Sensors, Blind Spot Monitoring)
  • Description/Symptoms: False alarms or complete failure of parking sensors or blind spot monitoring system. Error messages on the dashboard.
  • Solution: Replacement of the faulty sensor.
  • Estimated Cost to Fix: $300 - $600+ per sensor
  • Recalls: None Found

Exterior

• No Issues Found

Interior

• Rattling Noises from Dashboard or Trim Panels
  • Description/Symptoms: Annoying rattling or squeaking noises emanating from the dashboard or trim panels, especially on rough roads.
  • Solution: Securing loose trim panels or applying felt tape to areas causing friction.
  • Estimated Cost to Fix: $100 - $300+
  • Recalls: None Found

Summary

The 2021 Mercedes-Benz GLB 250 generally provides a luxurious and practical driving experience, but potential buyers should be aware of some common issues. Engine oil leaks and transmission issues like rough shifting can be moderate in severity and cost. Electrical problems, particularly with the MBUX system, can be frustrating but often resolved with software updates. While these problems aren’t necessarily widespread, a thorough inspection and a pre-purchase diagnostic check are recommended to identify any potential problems before buying.