2018 Mercedes-Benz GLS450 Owner Complaints

January 2023 - Airbag suspension failed. Replaced by Mercedes dealership. December 2024 - Airbag suspension failed. Replaced by Mercedes dealership. April 2024: First brake failure. The brakes stopped while driving. Repaired. April 2025: Second brake failure. Brakes failed again. Repaired. The mechanic stated the line was too close to the wheelbase, resulting in a pinpoint-sized hole. No warning lights. July 2025: Engine failure - the vehicle experienced a complete shutdown while driving with no warning lights. Vehicle in shop for 6-8 weeks for engine replacement by certified Mercedes mechanic. Post-engine replacement (July - Nov 2025) - Severe oil leaks at left cylinder head, small leaks at right cylinder head. Coolant warnings and overheating despite adequate coolant. Radiator and vent line issues. Active Brake Assist Limited warning appeared. Late November - Vehicle emitted smoke and experienced a small engine fire, observed under hood after stopping. Mercedes dealership deemed car unsafe to drive. During engine replacement wood pieces were found where destroyed motor mounts should have been. Multiple issues with no notice or warning lights.

NHTSA ID

11703281

Incident

Dec 4, 2025

Brake brakes are terrible. They have other years that they’ve acknowledge that the break are spongy and at times does not break the GLS has that defect. Also smell of gas fumes inside the vehicle. Please direct me the right way and help me with this issue. The brake issue almost have caused me two major accidents car doesn’t stop mechanic says this is a Mercedes issue You may contact me at [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11683217

Incident

Aug 11, 2025

When attempting to rise/lower the automatic suspension, the compressor cooling notification pops up, followed by a malfunction. After this occurs, the vehicle is incredibly bumpy, to the point of it being unsafe to drive. The vehicle has been repaired twice already by the dealership under extended warranty and the condition has occurred a third time in less than three weeks. This is our family vehicle, and we cannot drive it due to the risk of shaken baby syndrome for our infant because of how much it bumps. Videos are available to show just how bad it is.

NHTSA ID

11656041

Incident

Apr 1, 2025

This 2018 gls 450 has issues with suspension system. Bought this car in 2023 and using since Jna 2023 and suspension system failed like 3 -4 times. Mechanic changed the air compressor , valves and others and still the car has same issue. It used to lift the car to adequate height but the compressor keeps on pushing it to cause teh compressor to fail.

NHTSA ID

11654511

Incident

Apr 14, 2025

Third row seat will not lock. Warning message came on several months ago. I brought the vehicle in for service in may of 2022 to Mercedes Benz of Westwood MA. They neglected to repair the issue with the seat and returned the car back to me with the safety issue still unresolved. I spoke with the dealer and Mercedes Benz USA and they refuse to repair the vehicle under warranty even though it was still covered under the factory warranty. [XXX], the service manager at the dealership informed me that the third row seat motor needs to be replaced in order for the seat to lock. He said it is a very common problem with my model vehicle and that is the reason why the manufacturer wont cover the cost of repairing this safety issue. The dealer says the cost for this repair is 1750.00. We are worried that if we have a passenger in the third row seat, they may be injured due to seat not locking. I believe this is a widespread safety issue and I believe it should be covered under a voluntary recall. INFORMATION Redacted PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6).

NHTSA ID

11499082

Incident

May 1, 2022

While driving our 2018 Mercedes GLS 450 down Highway 80 just outside Sacramento, CA, the stationary glass panel of our panoramic sunroof spontaneously explpoded. There was no impact by any outside force, it just shattered with the sound similar to a gunshot. Fortunately I did not lose control of the vehicle, and thankfully the sun shade was closed otherwise broken glass would have showered down into my vehicle. this happened in early evening (around 7:00PM and the ambient temperature was 66 degrees outside, so this had nothing to do with temperature either. Mercedes Benz told me that since I am 3 months outside of warranty they would do nothing to help us and I would need to have this repair done on my own. Mercedes Benz of Walnut Creek, CA has inspected the vehicle and we're in the process of having the claim approved through my insurance. Completely unacceptable that this would happen on this (or any other vehicle). There is a class-action lawsuit against Mercedes for this exact same problem across a number of their models, so this is not an isolated incident. Had my wife been driving, she could have been startled to the point of losing control of the vehicle, possibly causing serious injury or death.

NHTSA ID

11457706

Incident

Mar 5, 2022

The contact owned a 2018 Mercedes Benz GLS450. The contact stated that after turning the ignition switch off, the driver suddenly discovered flames were coming from the engine compartment. The fire department was called to the scene and extinguished the flames. During the incident, the vehicle was destroyed and later towed away. A fire report was taken at the scene. The cause of the failure was not determined. The manufacturer and local dealer were notified of the failure. The VIN was not available. The failure mileage was 15,000.

NHTSA ID

11436804

Incident

Jul 15, 2019

Mileage

15,000 mi

PART OF MY PANORAMIC SUNROOF SPONTANEOUSLY SHATTERED WHILE SITTING AT A STOPLIGHT. THERE WERE NO CARS OR TREES AROUND AT THE TIME. NOTHING TOUCHED THE CAR WHEN IT HAPPENED.

NHTSA ID

11386871

Incident

Jan 6, 2021

Mileage

22,689 mi

I WAS ALREADY 90% IN PARKING LINE WHICH IS HANDICAP'S. ABOUT TO STOP RIGHT FRONT OF HANDICAP SIGN, SUDDENLY VEHICLE START MOVING FORWARD WHILE MY FOOT WAS IN BRAKE SO I PUSH LITTLE HARD TO COMPLETE STOP BUT VEHICLE SUDDENLY ACCELERATE FORWARD SMASHING INTO THE BUILDING GLASS ENTRY WALL AND DOOR. I AM SO CERTAIN THAT MY FOOT WAS IN BRAKE. I WANT TO KNOW THAT IS THERE ANY WAY SOMEONE CALL OR VISIT WHERE BODY SHOP TO INSPECT THE VEHICLE SO I CAN ASK MANUFACTURE TO REPLACE MY VEHICLE.

NHTSA ID

11353649

Incident

Aug 24, 2020

I TOOK THE CAR TO THE SERVICE 3 TIMES IN 4 MONTHS. THERE ARE MANY PROBLEMS WITH THE CAR. THE FIRST PROBLEM WAS THAT THE LEFT REAR SHOCK WAS LEAKING WHICH MADE A SQUEAKING NOISE WHEN DRIVING. THERE WAS ALSO AN ODOR PROBLEM WITH THE CAR THAT WAS COMING FROM THE VENTILATIONS. THESE TWO PROBLEMS WERE FIXED. I TOOK THE CAR ANOTHER TIME. THERE WAS ANOTHER PROBLEM WITH THE ECO START/STOP FUNCTION AND A PROBLEM WITH THE CAR TRUNK ONLY CLOSING HALFWAY. THE ECO START/STOP FUNCTION WAS FIXED BUT THEY SAID THAT THEY DIDN'T DETECT A PROBLEM WITH THE TRUNK. THE THIRD TIME I TOOK IT TO THE SERVICE I PROVIDED A VIDEO FOR THE TRUNK ONLY CLOSING HALFWAY AND I ALSO HAD ANOTHER PROBLEM WITH THE BLINDSPOT DETECTOR. MY WIFE WAS ALMOST GONG TO GET INTO AN ACCIDENT AS A RESULT OF THE BLIND SPOT NOT SHOWING UP WHEN SHE WAS MOVING TO THE LEFT LANE. I TOOK A VIDEO OF THE BLIND SPOT DETECTOR NOT WORKING PROPERLY. THEY WERE ABLE TO FIX THE CAR TRUNK AND SAID THAT THE BLIND SPOT DETECTOR WAS FIXED, BUT I HAVE NO FAITH IN THE COMPANY BECAUSE I HAVE HAD MANY PROBLEMS WITH THE CAR. THIS IS A NEW CAR THAT WAS MADE IN 2018, AND IT ALREADY HAS HAD MANY PROBLEMS WITH IT IN THE PAST MONTHS. WE CALLED THE MERCEDES MANUFACTURER IN THE US ABOUT THESE PROBLEMS. THEY SAID THAT THEY WILL GET BACK TO ME BUT HAVE NOT SAID ANYTHING. I TRIED CALLING THEM BACK BUT THEY WOULDN'T ANSWER ME. WE TOOK THE CAR FROM A MERCEDES CAR DEALERSHIP. THE ATTACHMENTS ARE COPIES OF THE SUMMARY OF THE THREE SERVICES THAT I WENT TO. THIS IS A NEW CAR AND IT ALREADY HAS THIS MANY PROBLEMS.

NHTSA ID

11299367

Incident

Dec 17, 2019

Mileage

8,000 mi

I FOUND OUT THAT ONLY ON 2018 MERCEDES GLS MODELS, THE CAR LETS YOU TURN OFF THE ENGINE WITHOUT A WARNING AND PUTS THE CAR IN NEUTRAL AUTOMATICALLY. IT DOES NOT PUT THE CAR TO 'P' OR GIVES YOU A WARNING SAYING YOU NEED TO PUT THE GEAR TO 'P' TO STOP THE CAR. I HAVE NEVER SEEN SOMETHING LIKE THIS IN ANY CAR. BASICALLY YOU BRAKE AND STOP THEN TURN OFF THE ENGINE WITH THE BUTTON. THE CAR SHIFTS TO 'N' INSTEAD OF 'P' AND IF YOU RELEASE THE BRAKE THE CAR SLIDES SINCE IT IS IN NEUTRAL. EVEN OLDER CARS DO NOT LET YOU TURN OFF THE ENGINE BEFORE SHIFTING TO P AR NEVER CARS JUST AUTOMATICALLY SHIFTS TO P WHEN YOU TURN OFF THE ENGINE. SINCE AS DRIVERS WE ARE NOT USED TO THIS, I CAN SAY THAT I HAD THE CAR SLIDE AT LEAST 5 TIMES THIS WEEK -FTER LEASING THIS VEHICLE. I CALLED MERCEDES AND THEY ACKNOWLEDGE THE ISSUE BUT THEY SAY THIS IS HOW THIS PARTICULAR CAR WAS BUILT. IT IS VERY DANGEROUS AND A NEVER BEFORE SEEN ISSUE WITH ANY CARS I HAVE DRIVEN OVER 25 YEARS I HAVE BEEN A DRIVER. THE OPERATING MANUAL ALSO STATES THAT THE CAR SHIFTS TO N WHEN TURNED OFF.

NHTSA ID

11150448

Incident

Nov 2, 2018

Mileage

10 mi

TL* THE CONTACT OWNS A 2018 MERCEDES-BENZ GLS450. WHILE DRIVING 70 MPH, THE VEHICLE LOST POWER AND ALL THE WARNING INDICATORS ON THE INSTRUMENT PANEL ILLUMINATED. ALSO, WHEN THE BRAKE PEDAL WAS DEPRESSED, THE VEHICLE FAILED TO STOP. THE CONTACT STATED THAT THE VEHICLE FINALLY STOPPED UPON REACHING A HILL. THE VEHICLE FAILED TO RESTART AND WAS TOWED TO FLETCHER JONES MOTORCARS (3300 JAMBOREE RD, NEWPORT BEACH, CA 92660, (949) 718-3000). THE DEALER DIAGNOSED THAT THE WIRING HARNESS MELTED. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS NOTIFIED OF THE FAILURE AND A COMPLAINT WAS OPENED. THE FAILURE MILEAGE WAS 200.

NHTSA ID

11118382

Incident

Aug 2, 2018

Mileage

200 mi

THIS IS A COMPLAINT ABOUT THE STEERING PILOT PART OF THE DRIVER ASSISTANCE PACKAGE OPTION I HAVE ON MY 2018 MERCEDES-BENZ GLS-450. THE STEERING PILOT IS SO POORLY DEVELOPED IT HAS ALMOST CAUSED ME TO CRASH SEVERAL TIMES, SO I HAVE TURNED IT OFF MOST OF THE TIME. THE MBUSA WEBSITE SAYS OF STEERING PILOT, ' THE STEERING PILOT FEATURE HELPS THE DRIVER KEEP THE VEHICLE CENTERED BETWEEN LANE MARKINGS WHILE CRUISING ON STRAIGHT ROADS, OR EVEN IN GENTLE CURVES.' NOTHING COULD BE FURTHER FROM THE TRUTH. WHEN DEPLOYED, STEERING PILOT CAUSES MY VEHICLE TO WANDER BACK AND FORTH IN THE LANE AS A DRUNK DRIVER WOULD, OFTEN CROSSING THE CENTER OR GUTTER LINE, ACTIVATING LANE KEEPING ASSIST. THE VEHICLE TENDS TO DRIVE TOWARD THE LEFT OF CENTER, NOT IN THE CENTER OF THE LANE. STEERING PILOT TRIES TO TAKE OFF RAMPS TO THE LEFT OR RIGHT FROM THE FREEWAYS, AND TRIES TO TURN DOWN STREETS ON SURFACE ROADS WHEN I WANT TO GO STRAIGHT. IT APPEARS TO HAVE NO LEARNING OR UPDATE CAPABILITY, EVEN THOUGH THERE IS AN INTERNET STATION IN THE VEHICLE. I PRESUME MB ENGINEERS ARE MONITORING STEERING PILOT'S PERFORMANCE AND CAMERA PICTURES, BUT WHY NO UPGRADES IN PERFORMANCE LIKE MY TESLA FRIENDS ENJOY WITH THEIR AUTO DRIVE SYSTEMS? THE STEERING PILOT SEEMS TO BE ADVERTISED AS MUCH MORE CAPABLE THAN IT REALLY IS, AND IS SO DANGEROUS I THINK IT PROBABLY SHOULD HAVE NEVER BEEN OFFERED UNTIL IT WAS MUCH MORE DEVELOPED!

NHTSA ID

11098029

Incident

May 25, 2018

Mileage

8,000 mi

MY GLS-450 HAS THE 'LIGHTING PACKAGE' WITH ACTIVE LED HEADLAMPS INCLUDING 'CORNER-ILLUMINATING FRONT HEADLAMPS, ACTIATED (ACTIVATED SPELLED WRONG) BY THE STEERING WHEEL OR TURN-SIGNAL USE, BRIGHTEN YOUR WAY INTO DRIVEWAYS AND GARAGES.' AS I LIVE IN A VERY DARK RURAL AREA, I ORDERED THESE LIGHTS. I SOON DISCOVERED THAT THE LEDS, WHILE SUPERIOR FOR FORWARD LIGHTING,PROVIDE LITTLE OR NO SIDE LIGHTING FOR THE DRIVER TO SEE WHEN TURNING ONTO DIVIDED HIGHWAYS WITH DARK ISLANDS, ETC. THIS IS BECAUSE THE LEDS ARE VERY STRAIGHT SHOOTING FORWARD. BUT THIS LED LIGHTING PACKAGE WAS SUPPOSED TO HAVE "CORNERING LIGHTS" ACTUATED BY TURN SIGNAL OR LOW SPEED WHILE TURNING WHICH SOLVES THIS PROBLEM. I HAD ALREADY EXPERIENCED THE ADVANTAGE OF THESE 'CORNERING LIGHTS' ON MY WIFE'S 2014 MERCEDES-BENZ GLK-250. BUT MY VEHICLE IS MISSING THE 'CORNERING LIGHT' FEATURE. IN CHECKING WITH THE DEALER AND MBUSA, THEY SAY THIS IS BECAUSE NHTSA WILL NOT ALLOW "CORNERING LIGHTS" ON THE GLS-450 BECAUSE OF THE HEIGHT OF THE HEADLIGHT UNIT ABOVE THE GROUND. COULD THIS BE TRUE? LACK OF CORNERING LIGHTS IN THE ACTIVE LED HEADLIGHTS MAKES CORNERING IN THIS VEHICLE UNSAFE AT NIGHT, AND THE LAMP HEIGHT RULE, IF THERE IS ONE, SHOULD BE MODIFIED AND RECALL ISSUED FOR GLS 450 VEHICLES WITH DEFECTIVE ACTIVE LED HEADLIGHTS MISSING THE CORNERING LIGHT FEATURE THEY ADVERTISE AS INCLUDED (SEE MBUSA.COM BUILD YOUR GLS450, LIGHTING PACKAGES). PLEASE TAKE ACTION ON THIS AND LET ME KNOW YOUR DECISION. THANK YOU!

NHTSA ID

11098025

Incident

May 25, 2018

Mileage

8,000 mi