W204 C63 Fuel Odour

[pharmoun]

Greetings to all,

Recently, while driving my 2014 C63, I have observed a faint odour of petroleum in the cabin. This scent fluctuates but has been increasingly noticeable.


There is no odour in the engine compartment and no discernible leaks present. The vehicle is entirely stock and operates smoothly without any warning lights on the dashboard or stored error codes. I am uncertain about what to inspect; does anyone have any advice?

Thank you very much

[markjay]

I would elevate the rear seat base, detach the two circular black covers, and examine the tops of the two sender units.

[pharmoun]

Thank you, I will examine it. Are the gaskets or plastic susceptible to failure?

[markjay]

Plastics may fracture, and the earth terminal for the pump can overheat and then melt. A few possibilities. May not be present, but certainly merits investigation.

[pharmoun]

Thank you; I will review it this weekend.

[Black_raven]

🫠

[paulh2602601]

I was on the verge of initiating my own discussion, but your

[paulh2602601]

I was on the verge of initiating my own discussion over this matter, but your description closely mirrors what I would have said for my 2014 C200 S205.

This phenomenon has only recently commenced for me, during the past week. Does it pertain to the cooler weather? A similar discussion on this forum discusses a fuel pipe that is susceptible to leakage. This pertains to a C350e, so may not be applicable in this context.

[Black_raven]

My 2013 204 was equipped with the identical M274 engine as yours (albeit in a 1.6 variant) and experienced a fuel leak in the flexible hose connecting the rigid underbody fuel line to the High Pressure Fuel pump located at the rear of the engine.
Upon replacement, the garage observed a modified component number for the hose and clip.
The odour of fuel in my automobile was distinctly perceptible beneath the hood and via the air vents into the interior.