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Mercedes-Benz GLC 300Model year report

2018 Mercedes-Benz GLC 300 Problems

Compared with other Mercedes-Benz GLC 300 years

Typical for this model

48/100 1.0× a typical year · 50 = typical

Nearby years with fewer complaints than typical and no open NHTSA investigation: 2019

Based only on NHTSA complaints, recalls and investigations. Not adjusted for how many vehicles were sold, and not a reliability rating. How this is calculated

Complaints
87filed with NHTSA
Median mileage
10,500miles, 31 complaints with mileage
Recalls
12campaigns on record
Trend
RisingComplaints filed in the last 3 full calendar years are at least 25% higher than in the 3 years before.
NHTSA crash rating
5 / 5stars overall, 2 rated versions
EPA fuel economy
24 mpgcombined, 2.0L 4-cyl RWD · 22 city / 28 hwy

Sources: NHTSA records for the 2018 Mercedes-Benz GLC 300 (complaints, recalls, investigations), NHTSA crash tests, EPA fuel economy. Report an error

What owners report

Owners of the 2018 GLC 300 most often describe two patterns: a check-engine light traced to the crankcase ventilation (PCV) valve, frequently reported at low to moderate mileage, and various electrical and transmission-symptom complaints. A number of reports involve the vehicle shifting out of Drive on its own, steering-wheel controls and air bag warnings, and trim or sunroof panel separation; many of the low-mileage filings concern brake noise and pedal-area carpeting.

  1. Engine

    Crankcase vent (PCV) valve failure, check engine light

    • 25 complaints (29%)
    • typically at 5.8 yrs old
    • owner-quoted repair $2,000 (median of 7 quotes)
    • filed 2022–2026

    Owners report a check engine light with a P052E code, described by dealers as a crankcase ventilation regulator valve or PCV intake line malfunction. Complaints describe rough running, hesitation on acceleration, a high idle and, in some cases, oil reaching the engine control unit. Several owners say the repair was quoted at roughly $1,000 to $2,000 and that it recurred after being replaced; others report warranty coverage disputes over related damage. Reported from a few thousand miles up into the 70,000s, with many filings in the 35,000-80,000 mile range.

    What to check: Ask for service records showing whether the crankcase ventilation valve or intake line has been replaced, and scan for stored P052E codes before buying. Check for oil residue around the engine computer area.

    2 excerpts from owner complaints in NHTSA records

    “I have had to replace the faulty pcv valve in my vehicle every 11 months since I have owned it. At over $1,000 a piece and with this being a well known problem with this make of vehicle the company needs to fix this problem. There are thousands of complaints online about this. Thank you for your time. Since this is an emission component the extended warranty will not cover it.”

    NHTSA complaint #11571765, filed 2024-02

    “Check engine light came out for a couple of days then went off. It appeared on the dashboard on 4/21/23 and disappeared 4/24/23. The day it went off, a message appeared on the dashboard stating to check coolant levels. A mechanic ran the diagnostics and it showed up as “positive crankcase ventilation regulator valve performance”. I’ve had this vehicle for only a year and I’ve only taken it to Mercedes. Is this car going to go up in flames?”

    NHTSA complaint #11518589, filed 2023-04
  2. Transmission and drivetrain

    Transmission slips into Neutral or stalls while driving

    • 14 complaints (16%)
    • median 8,000 mi at 1.4 yrs old (6 state mileage, few)
    • 3 mention a crash, fire or injury
    • filed 2018–2025

    Complaints describe the vehicle dropping from Drive into Neutral on its own, refusing to engage a gear, or shutting off with a transmission malfunction message. Owners report the car losing power at speed or at a stop and needing to be restarted or towed, and several mention diagnostic codes tied to the transmission control unit or wheel sensors. Some report a dealer software or control module update as the attempted remedy. Spread from a few hundred miles up to about 90,000 miles, with several reports between roughly 10,000 and 60,000 miles.

    1 related service bulletin

    What to check: During a test drive, watch for delayed or hesitant gear engagement and any warning messages in the cluster, and ask whether transmission control software updates have been applied.

    2 excerpts from owner complaints in NHTSA records

    “'the first incident - occurred in august when I stopped at a stop-light. I started driving when the light turned green and the car was accelerating as normal. There were cars behind me accelerating as well as normal. My SUV automatically shifted from drive to neutral by itself as I continue to accelerate to move with the normal flow of traffic. …”

    NHTSA complaint #11140717, filed 2018-10, 6,000 miles

    “The steering column stalk controls drive, reverse, neutral and parking. I stopped the vehicle on an incline in a parking lot. I had my foot on the brake. I shifted into neutral. The engine was still running. I thought I pushed the park button but the car rolled back into another vehicle.”

    NHTSA complaint #11144554, filed 2018-10, 3,200 miles
  3. Air bags

    Air bag warning light and steering wheel (clock spring)

    • 7 complaints (8%)
    • median 61,350 mi at 6.9 yrs old (4 state mileage, few)
    • 1 mention a crash, fire or injury
    • filed 2020–2025

    Owners describe an air bag warning light, loss of horn and steering-wheel button functions, and sometimes a clicking or clanking noise when turning the wheel. Complaints say dealers or independent shops traced this to the clock spring or air bag control unit and quoted replacement, and some note the vehicle was not covered by an air bag recall for the same symptom. Mostly reported between about 50,000 and 72,000 miles.

    Recall 18V838000Recall 17V627000Recall 18V208000

    What to check: With the ignition on, confirm the air bag warning light self-tests and goes out, and check that the horn and all steering-wheel buttons work. Ask whether any air bag recall work was performed for this VIN.

    2 excerpts from owner complaints in NHTSA records

    “All of the buttons on my steering wheel including the horn stopped working. I hear a clicking noise when i turn the steering wheel and the passenger air bag light randomly goes on and off. This leads me to believe the clock spring is broken. If the clock spring is the problem, this could create an airbag malfunction causing it to not deploy when needed or randomly deploy while i’m driving.”

    NHTSA complaint #11535378, filed 2023-07

    “While driving my SUV, I turned a corner and I heard and felt a wire or wires pull and snap inside the steering wheel. I then found that I could not operate any of the controls on the steering wheel and the driver side airbag light came on with a disabled message on the display. I think that it is the clock spring inside of the steering wheel that got caught up and snapped from me turning the wheel.”

    NHTSA complaint #11475794, filed 2022-07
  4. Body and structure

    Roof panel and panoramic sunroof separation or breakage

    • 7 complaints (8%)
    • median 16,000 mi at 1.8 yrs old (3 state mileage, few)
    • filed 2018–2026

    Complaints describe the exterior panel between the windshield and the sunroof detaching at highway speed, and in other cases the panoramic glass shattering with a loud report while driving. Owners report dealer diagnosis of failed adhesive bonding on the panel, and some relate the symptom to roof and sunroof recalls while noting their VIN was not included. Reported across a wide range, from around 10,000 up to about 51,000 miles, often at highway speeds.

    Recall 23V854000Recall 21V197000Recall 17V715000

    What to check: Inspect the panel ahead of the sunroof for lifted edges, gaps or uneven bonding, and ask whether the roof and sunroof recalls were completed for this VIN.

    2 excerpts from owner complaints in NHTSA records

    “Was driving down highway during clear sunny day on 12/21/18 at about 2:30 pm on I-10 east just outside of houston when my sunroof suddenly exploded outward. No signs of any debris being flung up or striking sunroof and there were no vehicles close to us at the time.”

    NHTSA complaint #11163043, filed 2018-12, 10,500 miles

    “My panoramic sunroof shattered while I was driving on the highway. There was a loud, sonic noise, like a gunshot and the glass shattered. There were no large trucks near me and after checking the roof, there was no object on the roof that could have caused it.”

    NHTSA complaint #11531489, filed 2023-07

Buying note. Get a pre-purchase scan for stored codes, especially P052E, and review service history for crankcase ventilation work, transmission software updates and completed recalls. Check the air bag warning light, steering-wheel controls, roof panel bonding and rear seat belts on a test drive.

Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.

NHTSA recorded 87 consumer complaints for the 2018 Mercedes-Benz GLC 300. 31 of the complaints include a mileage, and 77% of those were filed for vehicles with under 50,000 miles; the median is 10,500 miles. Of all complaints, 4 involved a crash, 1 a fire, 2 an injury, according to the filers. NHTSA lists 12 recall campaigns and 210 technical service bulletins for this model year. Compared with the other 7 Mercedes-Benz GLC 300 model years that have at least 25 complaints and are old enough to compare, this one scores 48 out of 100, where 50 is a typical year for the model (typical for this model). The comparison allows for the era and for how long each year has had to collect complaints, but not for how many vehicles were sold.

Which parts are reported most

Complaints can name more than one part, so the counts add up to more than the total. Select a part to see its complaints, recalls and bulletins.

Also reported: Steering (3), Vehicle speed control (3), Visibility (wipers, defrost, mirrors) (3), Back-over prevention (rear camera) (1), Electronic stability control (1), Exterior lighting (1), Lane departure (1), Latches, locks and linkages (1), Suspension (1), Wheels (1).

Example complaints

Engine: “Car failed to accelerate due to faulty fuel pump, fuel tank, etc. Car stopped and died several times in the middle of heavy traffic. Mercedes Benz of West Houston, Sewell Dealership, has my car that was towed to them late afternoon on 3/5/2024. I have owned a Mercedes for over 40 years and never had this occur or be scared due to the car’s lack of performance.”

NHTSA complaint #11576098, filed 2024-03

Other or unknown: “My work heels got stuck between the carpet and gas pedal creating a driving hazard. There is a gap that is dangerous and after notifying the dealer and mb, they said that I should not wear work heels. I am a professional woman and wear business shoes. The heel got stuck causing me to drive with no shoes on the freeway.”

NHTSA complaint #11071995, filed 2018-02, 200 miles

Electrical system: “When I was pulling into a parking spot at a low speed, the car accelerated and lurched forward, hitting a wall, which deployed the airbags. When the car started to accelerate, I hit the brakes but they did not engage.”

NHTSA complaint #11349114, filed 2020-08, 21,000 miles

Body and structure: “While driving on interstate 4 in Florida with our grandchildren going approximately 70 mph the sunroof on our 2018 Mercedes GLC just exploded no object came into the vehicle and while glass came into the vehiclenot all the glass that made up the sunroof came into vehicle suggesting a pressure issue as apparently blew out”

NHTSA complaint #11723228, filed 2026-03

Mileage when problems were reported

77% of the 31 complaints with a mileage were filed for vehicles with under 50,000 miles; the middle half falls between 3,200 and 35,000 miles.

45%0–1026%10–256%25–5019%50–753%75–1000%100–1500%150+
Share of complaints by mileage when the problem was reported, in thousands of miles (31 complaints with mileage). Red bars: under 50,000 miles. Bucket widths differ. Median: 10,500 miles.

Complaints by year filed

Trend: rising. Complaints filed in the last 3 full calendar years are at least 25% higher than in the 3 years before.

20182019202020212022202326202420252026
Complaints by year the complaint was filed with NHTSA. Red bars: the last 3 full calendar years used for the trend. The current year (2026) is partial.

Crash test ratings

NHTSA's 5-Star Safety Ratings for the 2018 Mercedes-Benz GLC 300. Frontal results are shown driver / passenger; rollover shows the star rating and NHTSA's estimated risk of rolling over in a single-vehicle crash.

VersionOverallFrontalSideSide poleRollover
GLC-Class · SUV 4WD★★★★★5 / 5554 · 18.4% risk
GLC-Class · SUV RWD★★★★★5 / 5554 · 18.6% risk

Driver aids listed by NHTSA for the 2018 model year: forward collision warning optional, lane departure warning optional, automatic emergency braking not available.

Neighbouring years: 2019: same overall rating. A redesign between years can change both the car and the test.

Source: NHTSA New Car Assessment Program (5-Star Safety Ratings), nhtsa.gov/ratings.

Fuel economy and running cost

EPA ratings for each 2018 Mercedes-Benz GLC 300 version. Annual fuel cost is the EPA's estimate at its current fuel prices for 15,000 miles a year (55% city driving).

VersionEngineTransmissionCityHwyComb.Fuel / yr
GLC300 RWD2.0L 4-cyl9-speed automatic222824$3,400
GLC300 4matic 4WD2.0L 4-cyl9-speed automatic212824$3,400
GLC300 4matic Coupe 4WD2.0L 4-cyl9-speed automatic222724$3,400

Source: U.S. EPA and Department of Energy, fueleconomy.gov. Ratings are for comparing vehicles; real-world mileage varies with driving and conditions.

Recalls and investigations

See all 12 recalls for the 2018 Mercedes-Benz GLC 300 → · Check a VIN at nhtsa.gov/recalls

Technical service bulletins

TSBs are manufacturer notes to dealers about known repair procedures. They are not recalls and do not by themselves mean a vehicle has a fault. 210 on record; the latest 10 are shown.

See all 210 bulletins →

Other model years of the Mercedes-Benz GLC 300

YearComplaintsMedian miRecallsCrash ★MPGScore (50 = typical)Trend
2025164,7003—27—Too new
2024212,1748—29—Too new
2023558,50012—2867 · MoreToo new
20226110,000252439 · TypicalRising
20216726,0009—2552 · TypicalRising
20206921,25016—2454 · TypicalRising
20194741,500125240 · FewerRising
20188710,5001252448 · TypicalRising
201710129,41612—2444 · TypicalRising
201613311,00012—2480 · MoreFalling

All Mercedes-Benz GLC 300 model years · Best and worst years by complaints

Frequently asked questions

What are the most common problems with the 2018 Mercedes-Benz GLC 300?

Owners of the 2018 GLC 300 most often describe two patterns: a check-engine light traced to the crankcase ventilation (PCV) valve, frequently reported at low to moderate mileage, and various electrical and transmission-symptom complaints. The issues reported most often: Crankcase vent (PCV) valve failure, check engine light; Transmission slips into Neutral or stalls while driving; Air bag warning light and steering wheel (clock spring).

How many NHTSA complaints does the 2018 Mercedes-Benz GLC 300 have?

NHTSA recorded 87 consumer complaints for the 2018 Mercedes-Benz GLC 300 as of Oct 27, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.

What part of the 2018 Mercedes-Benz GLC 300 is reported most often?

Engine is named most often, in 28 complaints (32% of the total), followed by other or unknown with 20.

Has the 2018 Mercedes-Benz GLC 300 been recalled?

NHTSA lists 12 recall campaigns for this model year. To check a specific vehicle, enter its VIN at nhtsa.gov/recalls.

How did the 2018 Mercedes-Benz GLC 300 do in NHTSA crash tests?

NHTSA's 5-Star Safety Ratings give the 2018 Mercedes-Benz GLC 300 5 out of 5 stars overall, across 2 rated versions (body style and drive). Ratings from different model years are only comparable when the vehicle was not redesigned in between.

What gas mileage does the 2018 Mercedes-Benz GLC 300 get?

The EPA rates the 2018 Mercedes-Benz GLC 300 (GLC300, 2.0L 4-cyl) at 24 mpg combined, 22 city and 28 highway, with an estimated annual fuel cost of $3,400 at 15,000 miles a year. Other engine and drive versions are rated differently.

At what mileage are problems with the 2018 Mercedes-Benz GLC 300 reported?

Among the 31 complaints that include a mileage, the median is 10,500 miles and the middle half falls between 3,200 and 35,000 miles; 77% were filed for vehicles with under 50,000 miles.

About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 27, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate. Crash ratings are from NHTSA’s New Car Assessment Program. Fuel economy is from the EPA and DOE (fueleconomy.gov).

Complaint counts come from NHTSA’s public complaint database; we count each complaint once. The source records for this vehicle are on nhtsa.gov. Scores and trends are our own summaries of that data, described in the methodology. This page is not legal, safety or repair advice: for a specific vehicle, check its VIN at nhtsa.gov/recalls and ask a qualified mechanic. See an error? Tell us.