Mercedes-Benz GLB 250

Known production deficiency: exhaust valve seat inserts and valve guides wear prematurely, leading to leaking combustion chambers. Mercedes extended warranty to 15 years / 241,000 km for model years 2019–2022.

Symptoms: Rough engine running, misfires (faults P0300–P0304), check engine light, power loss, vibration

On the M260 timing chain and tensioner can wear prematurely, especially with long oil change intervals. Affected vehicles show rattling on cold start.

Symptoms: Metallic rattling after cold start, check engine light, camshaft position fault codes

The wastegate actuator on the M260 can open prematurely from spring wear, leading to underboost. Diagnosis possible by pressure-testing the actuator.

Symptoms: Power deficiency under load, P0299 fault code, whistling on acceleration

On the M260 coolant lines and the thermostat housing cover can develop leaks. Mercedes carried out a service campaign (1204P59A93).

Symptoms: Dropping coolant level, coolant smell in engine bay, temperature rise, coolant level fault message

On 70,534 GLB X247 and A-Class W177 vehicles (production 2019–2020, Mexican manufacture only) the corrosion protection on the front axle subframe was inadequate.

On early production GLB X247 the body in the area of the front wheel arches was not correctly sealed. Water could enter the front footwell and damage control units.

On GLB X247 model years 2019–2020 the lateral spoiler elements on the tailgate could detach at high speed and endanger following traffic.