Replacing Fuel pump on M-Class ??? - PeachParts Mercedes-Benz Forum

Fast Robert · #1 07-09-2002, 10:22 PM

just after having a new fuel filter installed a couple months ago, I have begun to notice the fuel pump is starting to 'buzz.'

It does so when the system charges in preperation for ignition as well as when the vehicle is running.

Past experience with other vehicles indicate it is a sign this particular part is on its last legs and should be replaced ASAP.

My question is this:

Does the replacement entail removal of the back seat, peeling back carpet, etc. and accessing said part through the 'paint can lid' or is lowering the gas tank the preferred/correct method.

Vehicle background:

98 ML320, 117K miles (highway)

Also, any idea on the part cost for a new fuel pump? I'll be calling the source on this site tomorrow in prep for an

from the dealer.

As always, assistance is greatly appreciated.

Robert

Gilly · #2 07-09-2002, 10:33 PM

Robert:
I believe the buzzing is being caused by the fuel filter, not the pump. It is a known problem and is rectified by installing the new long filter and associated piping.
The method to replace the pump is the first option you mentioned, remove left side of rear seat and pull up carpeting and tank access lid. This will all need to be removed again to install the new fuel pipes for the updated filter.
Gilly

#3 07-09-2002, 10:35 PM

ML fuel pumps don't "buzz".
If you are hearing a noise from your
left rear wheel well it is probably
the fuel pressure regulator which is
located in the fuel filter. If you didn't have to
change the lines also then you installed a
old style filter. Do your self a favor and
get the new style with updated lines and install
it or just live with the noise. Sometimes it'll go away.
If You bought the filter from a dealer have them
parts warrenty it. Should be N/C to you to
replace I believe.

Emmett.

Fast Robert · #4 07-10-2002, 09:16 AM

gilly, cedes,

Thank you for the replies.

Looks like a trip to the dealer is in order as they recently replaced /upgraded the fuel filter and associated piping with new fitment.

Robert

Gilly · #5 07-10-2002, 04:16 PM

Since the update has been done, at least they won't need to remove the rear seat again. There was a bulletin about a squeeling noise from the filter, but now I can't remember, it mat actually be for the long filter, not the old short one.
Gilly

Champa · #6 07-10-2002, 06:10 PM

I complained about the high pitch noise, after they replaced the sending unit and piping, so they replaced the fuel pressure regulator. Now it is worst since it does it all the time, instead of occationally. I figured as long as it run I'll live with it till the warranty is close to expiring

Gilly · #7 07-10-2002, 07:53 PM

As cedestech pointed out, on this model the fuel pressure regulator is an integral part of the filter itsef.
Gilly