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EnginePart report

2015 Mercedes-Benz GL450 Engine Problems

Complaints
7about this part
Share
39%of 18 total for the year
Median mileage
98,115miles
Trend
Not enough dataFewer than 15 complaints, too few for a reliable trend.

NHTSA recorded 7 complaints about the engine of the 2015 Mercedes-Benz GL450, 39% of the 18 complaints for this model year. Where a mileage was given, the median is 98,115 miles. 2 a fire, according to the filers.

Fewer than 15 complaints name this part, so treat the figures as a rough indication only.

Example complaints

Selected from NHTSA records; personal details are removed. They are consumer reports, not findings.

“Plastic coolant union on radiator hose going from the coolant expansion tank to the electric auxiliary coolant pump catastrophically failed when I was changing the lh driver side front headlight bulb. I was leaning over the front of the vehicle with my head down to view the back side of the headlamp to remove the bulb, the plastic coolant union broke at this exact time shooting hot engine coolant all over my face. I've suffered 2nd and 3rd degree burns to my face, lips, neck and chest as a result. The vehicle engine was on, at idle speed, vehicle stationary in driveway.”

NHTSA complaint #11390996, filed 2021-02, 86,230 miles

“The rubber sealing around the lift gate failed on the vehicle and water seeped inside the vehicle and entire bottom of the vehicle underneath the floor board thereby damaging the electronic components, engine wire harness and headliner thereby rendering the vehicle was beyond repair. This issue led to mold to grow on the roof liner inside and on the seats which caused breathing issues for me and my family. This put our safety at risk! …”

NHTSA complaint #11457171, filed 2022-03

“To Whom It May Concern: I am writing to formally request the National Highway Traffic Safety Administration’s assistance regarding a critical safety defect in my 2015 Mercedes‑Benz GL 450 (M278 engine). I purchased this vehicle in October 2024 with 76,000 miles, and it now has about 87,000 miles. Alarmingly, I recently received a quote for $13,000 to repair a camshaft failure and extensive electrical damage. I was unaware of these issues when I purchased this car. I bought it under the illusion that it would be a safe vehicle for me and my children. …”

NHTSA complaint #11679345, filed 2025-08

“My 2015 Mercedes-Benz GLE 450 experienced an unexpected vehicle fire on Feb 13th 2026. The vehicle was just parked when I noticed smoke from the engine. The vehicle caught fire within a short period of time, and 911 was called. There was no known external cause for the fire. The incident appeared to originate from the engine compartment. This created a serious safety hazard and posed a risk of injury and property damage. The fire required immediate response from the fire department, and the vehicle was declared a total loss. The vehicle is currently in the possession of the insurance company. …”

NHTSA complaint #11728375, filed 2026-03

“The contact owned a 2015 Mercedes-Benz GL450. The contact stated that the vehicle was in the dealer for 12 days for an oil change. The contact's son drove the vehicle 2 days later, at an undisclosed speed when the vehicle started smoking from the engine. The contact's son pulled over when the vehicle caught fire completely. The fire marshals came out to extinguish the fire, there were no injuries. No police report was filed. The vehicle was not diagnosed nor repaired by an independent mechanic or dealer. The manufacturer was made aware of the failure. …”

NHTSA complaint #11500804, filed 2023-01, 110,000 miles

Related service bulletins

Engine: other model years

YearComplaintsShare of year
2016215%
2015739%
2014733%
2013924%
201112%
2009213%
200859%
200754%

Other parts of the 2015 Mercedes-Benz GL450

Other or unknown
3 complaints
Seats
3 complaints
Suspension
3 complaints
Electrical system
2 complaints
Transmission and drivetrain
2 complaints
Electronic stability control
1 complaints
Steering
1 complaints
Body and structure
1 complaints
Visibility (wipers, defrost, mirrors)
1 complaints

← All problems reported for the 2015 Mercedes-Benz GL450

About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 31, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.

To check a specific vehicle for open recalls, use its VIN at nhtsa.gov/recalls. Methodology