Petrol leak after filling up the tank

[SQ_W211]

Hello All,

I have just filled up the tank today and after filling when i was driving home i noticed some petrol smell but thought it must just be from my hands but since then i have parked the car and only just now noticed some spillage at the back behind the back driverside wheel. I have checked for any leaks but cn't see any active dripping and only just got the car MOT's which would indicate that the fuel lines werent damaged or rusted either.

Also checked the fuel capacity and its showing that i have full tank at 13.6 gallon which is what i always have after filling up to the brim.

Can anyone think of any obvious reasons why there may be spillage? Can this is be as simple as filling too much, but that should have meant that it leaked from the fuel cap after filled to the top or is there an inner valve inside the fuel neck which let fuel out if you have too much in the tanks?

I hope its not an issue with the tank or the filler neck.

Thanks in advance

 

[SQ_W211]

I have just started the car and can see a drop coming from under the back spring. Has anyone had this or know what it may be? I dnt want to be driving it as its obviously a fire hazzard

 

[Xtractorfan]

I think you may have overfilled, never a good idea as there will always be some spillage / wasteage, driving a few miles to bring the level down wont cause any problems, almost empty tanks are more dangerous than full tanks.. check again after you have gone a few miles when you get the car parked up..

 

[SQ_W211]

Thanks, I have just called out AA and surprisingly enough it stopped and he also said it may be overfilling and also taught me a rule of physics that petrol expands in heat which means it may have come out from somewhere. anyway i cnt see any drips now and it seems to be ok now

 

[television]

Your car is too new to have a few tank problem, never had one on here yet

 

[Bybuys]

I had exactly the same problem on a 2001 CLK convertible which I sorted last week. Part of the fuel filling system has a return pipe which is about 6 inches long and mine had perished. As it doesn't normally store fuel witin the pipe I just used some normal hose and replaced it. to do so you just removed the rear wheel and remove the wheelarch plastic liner. Its simple to do and took me about 30 minutes total. You'll need a couple of circular clips to secure it once you replace it.

 

[SQ_W211]

but mine wasnt actually leaking, i am told it was a simple over filling. I will be carefull and stop when the noozle clicks first time as i normaly try to get as much as i can

 

[Bybuys]

Thars fair enough Amo but I had an Indy check mine when on a hoist and he could see no signs of leaks and advised me only to fill to the first click. i did this and it still spilled out as you describe. Not necessarily the same problem but worth checking for 30 minutes effort. dangerous thing this old petrol stuff, specially if there are smokers about!!

 

[SQ_W211]

Agreed, I will do it over the weekend, this tank should keep me going till them and I have checked today everytime i parked up but there is no visible signs of leak. Also yesterday i could smell the petrol while driving it which hasnt come back since.

thanks for the advise though, i will get it checked

 

[SQ_W211]

Thars fair enough Amo but I had an Indy check mine when on a hoist and he could see no signs of leaks and advised me only to fill to the first click. i did this and it still spilled out as you describe. Not necessarily the same problem but worth checking for 30 minutes effort. dangerous thing this old petrol stuff, specially if there are smokers about!!

You were right, It happened again today. I went to MMT today and was told that it would be the return pipe. I will give it a bash tommorow. How easy is it to remove the inner liner under the wheel arch?

 

[television]

. I will give it a bash tommorow. How easy is it to remove the inner liner under the wheel arch?

Don't bash it too hard.

I can give you info on taking off the liner if you would like it

 

[Cole@MBS]

You were right, It happened again today. I went to MMT today and was told that it would be the return pipe. I will give it a bash tommorow. How easy is it to remove the inner liner under the wheel arch?

Sorry to correct you Amo, i said beather pipe, no fuel stains anywhere on your car!

 

[SQ_W211]

Sorry to correct you Amo, i said beather pipe, no fuel stains anywhere on your car!

Breather pipe? Ermmm.... I am confused now. so that's why you said it would be a long job? I am just not keen on having a puddle every time i fill up so just wanted to check if there is anything that can be done.

 

[SQ_W211]

Does anyone know where this Breather pipe is? Is this something i can attempt to fix myself?

 

[RiceBurner]

Thanks, I have just called out AA and surprisingly enough it stopped and he also said it may be overfilling and also taught me a rule of physics that petrol expands in heat which means it may have come out from somewhere. anyway i cnt see any drips now and it seems to be ok now

but mine wasnt actually leaking, i am told it was a simple over filling. I will be carefull and stop when the noozle clicks first time as i normaly try to get as much as i can

Always stop at the first cut-off. Modern filler-necks are designed to give you a full tank at the first cut-off.

And yes - fuel will expand quite considerably when it warms to the temperature of your car. Remember its been stored in a deep tank, underground. Even ambient air temperature is about 10 degrees higher than the temperature at which it's stored - especially in warm weather.

 

[SQ_W211]

Always stop at the first cut-off. Modern filler-necks are designed to give you a full tank at the first cut-off.

And yes - fuel will expand quite considerably when it warms to the temperature of your car. Remember its been stored in a deep tank, underground. Even ambient air temperature is about 10 degrees higher than the temperature at which it's stored - especially in warm weather.

when i filled up yesterday, i didnt even allow it to cut off, only filled upto what i thought would be full tank. It still leaked fair amount. I have at the filler neck checked which didnt have any stains so its clear that its not leaking from the filler neck. I was advsied it could be the breather pipe but not sure how i can go about checking that.

 

[SQ_W211]

Don't bash it too hard.

I can give you info on taking off the liner if you would like it

Malc, Can you provide me with this info? I am going to check this as first instinct and see if i can locate where the leak is coming from.

 

[shane10010]

Hi,

Same smell with mine, most noticable when on the drive (decline)
Is it definately the return hose? If it is, I will order a replacement and do next weekend.

Great advice, thanks!
Shane

 

[Coupe]

I'm getting a smell after filling up. I'm sure I've posted something on this in the past but don't seem to get any forum posts on a search for my name? Does anyone know the correct bore size of the pipes I need to order.

 

[Coupe]

Ok the pipe is 16mm Petrol Quality BUT you might as well get the original parts. From the photos the split pipe (other fractures as well elsewhere). New parts out and in the car. Parts cost with VAT £17.58 from Guildford Mercedes. Reasonable I thought and they had them in stock. Careful if looking at EPC as the parts do not show the bends but they do have them. Hope this helps someone. Hopefully when I fill up again it won't smell, taking precaution to not overfill. Should add pipe that goes into overflow tank (top left in car picture) has a wider diameter at end so it's difficult to use a single bore pipe. Hope this makes sense. You can just make it out on picture of new pipes out of car, top pipe left end.