Fuel pump going bad?




Have you ever been sitting at the light and a helicopter is nearby, especially a hughey, in the distance. You can hear the blades, but can’t see it? Thats kindve what it sounds like.
I have never had to replace a failing fuel pump in any car ever, and I am 49 years old. Kind’ve of hard to believe i’d need to on a 3 year old car with 52k miles, always Costco Premium fuel. So i thought I would ask if anyone has any knowledge of TSB’s from MB related to a fuel pump or fuel system issue? Or, a thumping noise coming from the rear underside when the engine is running?
Thanks!!
Have you ever been sitting at the light and a helicopter is nearby, especially a hughey, in the distance. You can hear the blades, but can’t see it? Thats kindve what it sounds like.
I have never had to replace a failing fuel pump in any car ever, and I am 49 years old. Kind’ve of hard to believe i’d need to on a 3 year old car with 52k miles, always Costco Premium fuel. So i thought I would ask if anyone has any knowledge of TSB’s from MB related to a fuel pump or fuel system issue? Or, a thumping noise coming from the rear underside when the engine is running?
Thanks!!




but i have to be honest, ive never known a tranfer case to make noise when the car isnt moving. Considering the noise happens when sitting still, and given how loud it is, i am a little surprised they had to hunt for it 3 times on yours. Seems like they could put it on the rack, turn it on, and immediately find it? Ours sounds like it is coming from underneath towards the rear of the car, which led me to believe either the fuel pump or an actuator related to the air suspension. Bit since it goes away immediately when the engine goes off, and doesn’t make a sound when i raise/lower rhe car, i ruled out the air suspension.
But if it becomes a “throw parts at it” hunting game, then this car is gone asap. Minor issues, annoying as they are (seat tears, misaligned window track) I can live with for a first model year run. But failing transfer case or issue like that, 3 years and 52k miles later (when manual calls for fluid change at 60k)? Thats a no-go for me. If it is the fuel pump, then I am 100% expecting Mercedes Benz to step up with some goodwill assist since I am out of warranty. Thats just crap if they don’t, for a repeat customer. Fuel pumps don’t go bad that soon when they’re not abused or constantly run on empty. We never go below ¼ tank for the very reason to keep the pump cool and lubricated, in all of our cars.
Have you ever been sitting at the light and a helicopter is nearby, especially a hughey, in the distance. You can hear the blades, but can’t see it? Thats kindve what it sounds like.
I have never had to replace a failing fuel pump in any car ever, and I am 49 years old. Kind’ve of hard to believe i’d need to on a 3 year old car with 52k miles, always Costco Premium fuel. So i thought I would ask if anyone has any knowledge of TSB’s from MB related to a fuel pump or fuel system issue? Or, a thumping noise coming from the rear underside when the engine is running?
Thanks!!




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ours still does it every now and then too. Doesn’t seem to impact the way it drives, and we’re 4 years and 70k miles down the road with ours. Not sure we’re willing to spend the time and money hunting for it until whatever it is breaks to reveal itself.
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Mercedes says performance degradation may occur before the pump fails outright, and a malfunction message will display in the instrument cluster if adequate fuel is not being delivered to the engine. Once the deterioration reaches that point, engine performance will likely be tangibly impacted. Mercedes will begin notifying dealerships of the recall campaign immediately; customers should expect notices to arrive in August. autoblog.com
It sure sounds like an impeller hitting the side of the fuel pump housing. I am just worried that it will fail out of warranty and I will end up with a huge bill to fix it.




Man, MB is racking up the recalls now on this car! Got one sitting on my desk for some computer transmission module, hear another is coming over a faulty 48v ground wire thing, and now this one. Think I'll just wait for this one to go live and then put it back into the shop for all 3 to get fixed at once. Oh joy....
The dealership has managed to fully resolve numerous issues, except for two: The harsh downshifting is now thankfully somewhat improved, with the most recent transmission update, and the driver's seat ventilation fan is now hitting something inside the seat, which makes an annoying noise (fan blades actually contacting something in there...)
My wife love the GLS, since it is Brilliant Blue (only offered in '20 and '21). And thankfully she is oblivious to almost all vehicular issues, so I just keep telling myself: "She's happy, and I have my W222 to console me...


I'm in a similar boat. It was a grudge purchase for my wife: "Happy wife, happy life"!
I remember Mercedes' better days but those are as fleeting as planned Superchargers!




They ended up replacing the entire gas tank and any associated parts like the fuel pump and valves. They said there was a noise from the charcoal cannister after that job, so they replaced that as well. The end result is the noise has stopped, but I don't know what was causing it. I'm still betting it was the fuel pump banging around within the fuel sender housing but that's a guess.




Pg 1 Fuel pump noise
Pg 2
Pg 3




End of the day, it sounds like perhaps it is related to the evap system, and perhaps the true recall ought to be the deformed vent valve itself.











