Fuel Filter Replaced - Now Humming

[VenomX]

Had my mechanic change the old fuel filter for a Mahle KL82 and two days later it makes this noise

Any idea why it is doing this ?

According to here, it can be caused by air in the system

https://www.mahle-aftermarket.com/media/media-global-&-europe/products-and-services/technical_messenger/tm_issues_2014/tm-sheet_5_2014_en.pdf

 

[Uncle Benz]

That sounds like the pump. I’d check the flow arrow on the filter is pointing the right way. Ah, 4 pipe one. The pipes need to be correctly placed too. I’ve changed loads, never had one humm

 

[VenomX]

That sounds like the pump. I’d check the flow arrow on the filter is pointing the right way. Ah, 4 pipe one. The pipes need to be correctly placed too. I’ve changed loads, never had one humm

Yeah the arrow points to the left.

 

[VenomX]

It only does it when the engine is running. Not when I turn the key twice to activate the fuel pump

 

[Trev1964]

Straight back to whoever did the work.

 

[VenomX]

Done some reading and other people have had the same issue with Mahle fuel filters.
I have bought a Mercedes genuine fuel filter which I Should hopefully fit next week. Is this the best idea ?

I provided the Mahle part to the mechanic so it is not their problem as they have definitely installed it correctly.

 

[VenomX]

That sounds like the pump. I’d check the flow arrow on the filter is pointing the right way. Ah, 4 pipe one. The pipes need to be correctly placed too. I’ve changed loads, never had one humm

Are Mercedes genuine parts usually OK ?

 

[Uncle Benz]

Are Mercedes genuine parts usually OK ?

Never ever had a problem with one

 

[VenomX]

I replaced the fuel filter with a Mercedes genuine and now the noise has disappeared and the car runs perfectly.

I am a bit concerned the engine could be running slightly lean as the MPG seems to be higher than before, and higher than what it should be around town according to the web.

No error codes, car runs perfectly. Any suggestions ? I did check for any leaks around the fuel filter after I fitted it and tightened up a couple of clamps and now seems to be dry.

 

[alexanderfoti]

Good news!

If it was lean, to the point of damaging the car, it would have a check engine light on with a rich adaption stop code.