What 20 owners told NHTSA about the 2021 Mercedes-benz GLA

Cowl vent grille openings allowed normal environmental debris to accumulate, plug drainage and divert water onto electrical components and potentially result in a fire if not addressed. Some of the debris passes through into the hvac system and cannot be cleaned without dealer removal/repair of the hvac motor, which costs the customer more than $500 in repairs and disincentivizes mitigation. Furthermore, Mercedes is aware of the problem, has not issued a customer satisfaction recall, and instead, is charging customers more than $1,000 to install a plastic protective shield to prevent accumulation of debris, clogged water management, and risk of fire.

NHTSA ODI 11743847

I recently purchased my vehicle with under 30k miles in July of 2026. Not long after my purchase my car began roughly idling with a blinking check engine light, and soon after the engine began misfiring. This also cause loss of power when attempting to accelerate creating dangerous conditions in high traffic/fast paced areas. After lots of research I found several reports of owners with cylinder failures. The dealership only responded to fixing the issue after calling them out directly on the issue.

NHTSA ODI 11729834

Component/System: Engine cooling and lubrication system. Coolant was found mixing with engine oil (milky oil), indicating internal engine failure (I was informed it could be oil cooler/housing, thermostat, head gasket, or related components). Vehicle is currently at an authorized Mercedes-Benz dealership and available for inspection. The front left inner lining of my front break pad also "failed" inspection and the other 3 front break pads say "caution" and I never received a notification or warning about my breaks. Safety Risk: Coolant contamination of engine oil can cause sudden engine failure or loss of power without warning, creating a serious safety risk while driving, especially at highway speeds. There was no indication that engine oil was mixing with coolant, check engine light failed to illuminate/ no diagnostic warning illuminated. The condition was discovered incidentally during routine maintenance, which prevented any opportunity for corrective action prior to the failure. Confirmation: The condition was confirmed by an authorized Mercedes-Benz dealership during routine maintenance. The dealership stated the failure was not caused by owner misuse.Inspection: Vehicle has been inspected by an authorized Mercedes-Benz dealership (manufacturer representative). No police or insurance inspection occurred, as there was no accident or external event. Warnings/Symptoms: No check engine light or diagnostic warning ever illuminated. The issue was discovered incidentally after I received a low battery voltage notification and a routine maintenance reminder indicating service was due in approximately 1,000 miles, which I arranged promptly. The manufacturer will not perform full diagnostic teardown to determine the root cause unless I pay approximately $3,000 out of pocket. Link to video: [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11715960

When coming to a full stop at a red light (or any need to idle at a stop), the car frequently begins to hesitate as if it is about to cut off. I assume it has something to do with the ‘fuel saving feature’ which comes on in the form of a green symbol in the lower left of the odometer display (the engine is still running the AC) . When you start to drive again the car always jerks before moving , on at least 3 occasions it has actually cut off completely and must be restarted (everything goes off) - it is big problem, especially in heavy traffic (horns blaring & angry drivers are encountered) I almost had a car hit me from behind; my car had jerked slightly when I began to accelerate and then shut off completely. It is definitely a dangerous defect. The Dealership emphasizes 93 Octane gas or higher to help with this issue- but I Always use the highest Octane gas I can find ! It has happened VERY often - I dread stopping at red lights and stop signs, one day it will cause an accident.

NHTSA ODI 11677929

I am reporting a potential safety and mechanical defect involving the cylinder head in the Mercedes-Benz GLA 250. Many owners, including myself, have experienced premature cylinder head failure, often without warning, leading to loss of power, engine misfires, rough idling, and in some cases, sudden engine shutdown while driving. This issue appears to be widespread among GLA models equipped with the M260/M270 engine, often occurring well before 100,000 miles. It raises serious concerns about the design, durability, and safety of the engine’s top-end components. Given the frequency and severity of this failure — and the high cost of repairs — I believe this warrants an official investigation and potential manufacturer recall. I urge the NHTSA to review similar complaints and initiate a formal inquiry into Mercedes-Benz’s awareness and handling of this defect. Thank you for your attention to this matter.

NHTSA ODI 11661372

Engine misfired in operation requiring an emergency stop while on a mountain road. Severe check engine light turned on (Mercedes has a two stage check engine light). Vehicle was parked for 20 minutes and battery was disconnected. This appeared to fix the issue. Vehicle was brought to dealer. Dealer stated the cylinder head for early 2021 GLA 250 engines had a casting flaw that result in hot gases escaping and damaging engine. Engine and turbo rebuilt under warranty at 17000 miles.

NHTSA ODI 11547873

I purchased this car approx 3 months after real issues began. My car would have issues idling where it would sometimes turn off at stop lights and require multiple reignition attempts before proceeding. This would also happen when the auto-start feature (anti-idle/gas saving) was engaged (which is the default in the system) and this posed major safety concerns. The unstable idling of the car would result in an initial acceleration after being stopped, shortly followed by the engine dying. There were multiple times I was at an intersection yielding before turning where this happened and it resulted in my being in the path of oncoming traffic without the ability to accelerate until the car restarted. I contacted my local Mercedes dealer who acted like this wasn't a big deal, but it is related to a known issue with a faulty cylinder head. They covered the repair under the manufacturer warranty, but told me to keep driving my car and promised it was safe until they could get the part in (because the didn't have a loaner car to provide). I found this very troubling. In conversations throughout the repair being completed, the dealer admitted that they know the part that was used for the year and model is bad, but they didn't want to do a recall and would wait for issues to come up. This is unacceptable because this absolutely is a safety concern as demonstrated by the example I shared. They should be required to do a full recall to address the safety concerns and I believe not disclosing this information was unfair to me as a consumer who did not have the information I needed to be informed on the reliability of this vehicle prior to purchase.

NHTSA ODI 11544109