Petrol leak

[Mark.merc]

I have a 2002 SL500 which has suddenly started to smell of petrol and when I checked the petrol flap it was leaking a small amount each time I took it out.
I replaced the petrol cap thinking it was that but it still leaks.
Any advice appreciated

 

[Petrol Pete]

When you open the filler cap is there a 'woosh' of air being released ?

 

[Mark.merc]

When you open the filler cap is there a 'woosh' of air being released ?

I’ve just checked and no there is no sound.
would I need to take the car on a run to check as I’ve had the cap off a couple of times this afternoon?

 

[Bobby Dazzler]

Where is the leak? If it’s the moisture in the black plastic surround shown in your photos, then that must be evaporation and condensation rather than a leak as it’s higher than the fuel level.

 

[Mark.merc]

Where is the leak? If it’s the moisture in the black plastic surround shown in your photos, then that must be evaporation and condensation rather than a leak as it’s higher than the fuel level.

Yes when I Open the petrol flap it’s in the bottom area as shown in the photos you can smell the odour of petrol as you drive along especially with the roof open

 

[Petrol Pete]

On many cars there is a 'closed loop' type of system so no liquid (fuel) makes it to the ground and fumes are either cycled back to the tank or sent to the engine via various pipes and sometimes a vapour ' filter' cannister that is sometimes behind the wheel arch liner on the same side of the fuel flap.

I can not comment further on you particular car but as Bobby says the fuel level in your tank would never be high enough to leak at the cap if filled in the correct manor.

 

[Petrol Pete]

 

[Petrol Pete]

Bit like this . ^^^^^This is a full evaporation system on a 2006 C class. Not sure what yours looks like.

 

[Mark.merc]

On many cars there is a 'closed loop' type of system so no liquid (fuel) makes it to the ground and fumes are either cycled back to the tank or sent to the engine via various pipes and sometimes a vapour ' filter' cannister that is sometimes behind the wheel arch liner on the same side of the fuel flap.

I can not comment further on you particular car but as Bobby says the fuel level in your tank would never be high enough to leak at the cap if filled in the correct manor.

Thank you for the info and I will certainly look into it.
it’s great to be part of a group with such in depth knowledge of cars

 

[Mark.merc]

Ok so an update on the Sl500 petrol smell after further investigation.
You can only smell it when the roof is down.
The only place it smells of fuel is drivers side rear wheel arch.
There is a small leak/evaporation inside the petrol flap but no whoosh sound when you unlock the cap.
Time to visit my local independent garage I’m just wondering if anyone knows what part might need replacing as an independent he’s probably not come across this before.
Many thanks