Whiny noise.

[Freza74]

Forgive the barrage of posts, I'm getting used to the merc ways.
E240, 2002 model.
There seems to be a noise coming from the rear when idling, sounds a bit whiny and its very audible. Could this be the intank fuel pump ?, or are there other things that could make that noise there ?.
I guess it could be from elsewhere but it sounds like it's from the rear passenger side somewhere.
Many thanks in advance

 

[Jobsworth]

Could be the pump, but look for history of the fuel filter being replaced first. They are often neglected, and a blocked filter will make the pump whine. If I had a pound for every blocked fuel filter I’ve seen, well, I could probably buy a pint, but it’s worth starting with the cheap bits

 

[AltonAnt]

I have that sometimes but more often she sits in the front

 

[mersum1es]

Alternator whines on rear speakers?

 

[Freza74]

Alternator whines on rear speakers?

Wow, Is that even a thing with these cars ?

 

[Jobsworth]

Wow, Is that even a thing with these cars ?

Tenuous. Why not the fronts too?

 

[mersum1es]

In aftermarket car stereos its a common problem, just came up my mind. Why only rear; if RCA cable go near power cables, alternator noise induce to RCA cables. Then there are possibilities with grounding, earth circuit, too high gain in line amplifiear etc. but depends highly on system and probably noise could heard from fronts too.

 

[mersum1es]

Another thought, you have PSE pump under rear seat, if there is a leak or something in vacuum system...

 

[Freza74]

Another thought, you have PSE pump under rear seat, if there is a leak or something in vacuum system...

What is a pse pump please ?

 

[Bert_W164]

Could be the pump, but look for history of the fuel filter being replaced first. They are often neglected, and a blocked filter will make the pump whine. If I had a pound for every blocked fuel filter I’ve seen, well, I could probably buy a pint, but it’s worth starting with the cheap bits

Do JD Weatherspoons still do a pint for £2? Or does a can (pint) of K/White Lightning or similar apply here, which would only cost around £1.50...

OP post a video with audio, it could prove helpful, trying to diagnose this in a fairly vague setting is like pissing in the wind - sure one can piss in the wind, but it'll go everywhere in a manner of directions and possibly on one self.

 

[mersum1es]

What is a pse pump please ?

Vacuum pump, feeding (vacuum) power to your trunk, rear headrest and door locks.