Skip to content
Mercedes-Benz GLS 550Model year report

2018 Mercedes-Benz GLS 550 Problems

Complaints
6filed with NHTSA
Median mileage
7,000miles, 5 complaints with mileage
Recalls
3campaigns on record
Trend
Not enough dataFewer than 15 complaints, too few for a reliable trend.
NHTSA crash rating
—no overall rating published
EPA fuel economy
16 mpgcombined, 4.7L 8-cyl 4WD · 14 city / 19 hwy

Sources: NHTSA records for the 2018 Mercedes-Benz GLS 550 (complaints, recalls, investigations), EPA fuel economy. Report an error

NHTSA recorded 6 consumer complaints for the 2018 Mercedes-Benz GLS 550. The part named most often is other or unknown, with 2 complaints (33% of the total), followed by brakes (1) and electrical system (1). 5 of the complaints include a mileage, and 80% of those were filed for vehicles with under 50,000 miles; the median is 7,000 miles. NHTSA lists 3 recall campaigns and 88 technical service bulletins for this model year. Other or unknown complaints overlap with 3 technical service bulletins filed under the same part. Brakes complaints overlap with 1 recall campaign and 2 technical service bulletins filed under the same part.

This model year has fewer than 25 complaints on record, so the numbers below can change a lot with a few new reports.

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.

Example complaints

Other or unknown: “I was driving in a rural area when all of a sudden I heard what sounded like an explosion. My first instinct was that I had blown a tire because it was so loud. However, the car was handling fine and no warning messages came on. My husband and I both said what was that? Everything on seemed fine mechanically so we kept driving, but a bit shaken by the sudden loud noise. I few hours later we stopped for gas. As my husband went to clean the windshield he noticed the shatter of the glass roof panel. We thought back to the incident earlier and realized that must have been the sound me heard. …”

NHTSA complaint #11154785, filed 2018-11, 7,000 miles

Brakes: “The contact owns a 2018 Mercedes Benz GLS550. The contact stated that when the brake pedal was depressed there was an abnormal noise detected. The brake warning indicator light was illuminated. The contact stated that the brake pad on one side of the disc was completely worn, and the other side of the disc was like new with a full thick pad. The vehicle was taken to the local dealer and the contact was informed that the brake rotor needed to be replaced. The vehicle was repaired. The manufacturer was notified of the failure however, no further assistance was provided. …”

NHTSA complaint #11429716, filed 2021-08, 4,500 miles

Electrical system: “Seatbelt had tightened and not released when my body moves. Brakes are not applied. Typically during driving I'm small enough to maneuver my hand down to release red seat belt button. I've had to stop my vehicle 5-10 times to release belt. I have 2 small kids 7/ 11 both are 60 pounds they are 4 feet tall and 4'6' 7 year old still uses booster I''ve checked belts to the best of my ability but I'm 110 lbs 5'2' and have no mechanical training or experience or certifications this has been noted to mercedes and the problem is never really discussed. …”

NHTSA complaint #11297292, filed 2020-01, 32,000 miles

Mileage when problems were reported

80% of the 5 complaints with a mileage were filed for vehicles with under 50,000 miles; the middle half falls between 4,500 and 32,000 miles.

60%0–100%10–2520%25–500%50–7520%75–1000%100–1500%150+
Share of complaints by mileage when the problem was reported, in thousands of miles (5 complaints with mileage). Red bars: under 50,000 miles. Bucket widths differ. Median: 7,000 miles.

Complaints by year filed

Fewer than 15 complaints, too few for a reliable trend.

201822020202120242026
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.

Fuel economy and running cost

EPA ratings for each 2018 Mercedes-Benz GLS 550 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
GLS550 4matic 4WD4.7L 8-cyl9-speed automatic141916$5,150

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

Recall details for the 2018 Mercedes-Benz GLS 550 → · 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. 88 on record; the latest 10 are shown.

See all 88 bulletins →

Other model years of the Mercedes-Benz GLS 550

YearComplaintsMedian miRecallsCrash ★MPGScore (50 = typical)Trend
201867,0003—16—Not enough data
2017654,0005—16—Not enough data

All Mercedes-Benz GLS 550 model years

Frequently asked questions

How many NHTSA complaints does the 2018 Mercedes-Benz GLS 550 have?

NHTSA recorded 6 consumer complaints for the 2018 Mercedes-Benz GLS 550 as of Nov 1, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.

What part of the 2018 Mercedes-Benz GLS 550 is reported most often?

Other or unknown is named most often, in 2 complaints (33% of the total), followed by brakes with 1.

Has the 2018 Mercedes-Benz GLS 550 been recalled?

NHTSA lists 3 recall campaigns for this model year. To check a specific vehicle, enter its VIN at nhtsa.gov/recalls.

What gas mileage does the 2018 Mercedes-Benz GLS 550 get?

The EPA rates the 2018 Mercedes-Benz GLS 550 (GLS550 4matic, 4.7L 8-cyl) at 16 mpg combined, 14 city and 19 highway, with an estimated annual fuel cost of $5,150 at 15,000 miles a year. Other engine and drive versions are rated differently.

At what mileage are problems with the 2018 Mercedes-Benz GLS 550 reported?

Among the 5 complaints that include a mileage, the median is 7,000 miles and the middle half falls between 4,500 and 32,000 miles; 80% were filed for vehicles with under 50,000 miles.

About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Nov 1, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate. 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.