rinosaur

I just replaced my fuel filter following the Install University instructions and everything went fine. However after 2 minutes of driving, I get this humming noise from the fuel pump. I searched elsewhere and found that the pump could be working double time to repressurize the system as I had depressurized the system before replacing the filter. I drove for 10 more minutes and its still making the noise. Is this a reasonable explanation? I was very careful in the installation of the filter.

PA_Pete

That's quite random, but not sure if it's bad or not. Are you sure it is the Fuel pump making the noise and not something else? I just did the fuel filter on my car as well, I de-pressurized the system, and did it on an almost empty tank. Not too bad, but still got a lot of fuel everywhere. Did you use the correct fuel filter? Were you sure that you didn't overtighten or kink any lines?

Glyn M Ruck

rino - the fuel pumps on these cars do make a noise. Some are more sensitive to it than others. As long as it's not drawing air anywhere - you would see a leak. Don't worry about it as long as the car is running OK. It's probably singing it's merry tune because it's no longer fighting with a half clogged fuel filter.

One good check - let the car stand overnight to bleed off fuel rail pressure. Then turn on the ignition while listening to the pump (don't crank). It's under the drivers side rear seat. The pump should start - bring the fuel rail up to pressure & then stop. The car is then ready to be cranked to start. If the pump does not stop when the fuel rail hits pressure then something is wrong. It should only start again once the engine is running.

rinosaur

Hey there it is running fine and I did check for fuel leaks and there were none. Thanks for the assurance. And after I do put it in 2nd position it does pump for 3 seconds and then stop.

Glyn M Ruck

Good news - don't worry then!

d1no

^Glyn is the mann.. lol

krisv420

Three days later.... His motor seized ... crap

hanknum

I replaced my filter a couple months ago and my wife has now just started to hear this humming noise. I did verify the noise and it did not do this previous to the filter change. It seems to do this after about 30 minutes of driving. Makes the car sound like a hybrid. Anyone have anymore info?

Nanda

Hello,
Hope this is the right place to post this.
I have a 2006 C230 sport (manual trans). I sometimes hear a high pitch noise from driver side rear seat and search in the forums suggest it could be from fuel pump (looks like a known issue).
Since the noise was not present always, I did some experiments by running it full tank, half tank etc. The only co relation that I can come up is that when the outside temperature is above ~80F (~25C), i get the noise. Sometimes the noise stops after some time (say 20 mins). I never got it in the mornings when it was cooler. The noise is present if i switch off the engine and start the engine immediately.
I changed the fuel cap seal and noise volume has come down but it's still loud enough to hear it clearly.
Fuel filter was changed ~40K Miles back.
I am planning to change the filter again.
I couldn't find a single answer online on what would fix this. Some have changed the fuel pump and still get the noise. I am not in a position to spend $ on fuel pump and still have the issue (also, i don't like to blindly change components hoping it will fix the problem).
Please suggest whether i am in the right direction to change the fuel filter and when else I could check.

Thank you for your time.