Fuel Leak

I have a fuel leak, advice, suggestions almost anything except Swan vesta matches welcome.

Now the story.
When I brought my MGF (2001 1. the very nice man said I need to get it MOT'd before you take it but as I have a garage I will get it done for collection at the end of the week. I said thank you and duly turned up at the end of the week to collect my shiny new (to me) car and pay the nice man some money.

MOT all done but almost as a throw away comment he mentioned, as I was leaving, that they had found a petrol leak but not to worry all sorted now.

The car has been fine and with the help of the how to guides and general banter on here I have been righting the wrongs of time slowly over the last 6 months. But always a slight smell of petrol.

It got worse, but, quite scientific. No noticeable puddle or mark where I park, but if I drive then put the car in reverse for a few feet, terribly strong smell. If I open the windows unbearable, if I keep the hood up and the windows closed, there but bearable. If I turn the heater fan to number 2 smell gone completely. (I suspect positive pressure)

Today I had to take wife to the station 40 miles away (we live in Cornwall) did not want to run out of petrol with her in car and booked to catch train so filled up. Smell no worse than usual and with heater on no smell at all. Got back fro station and with heater off it was unbearable. Removed the parcel shelf cover and the tank cover flap, no sign of leak but 2 bolts missing. Refitted smell just as bad, removed the carpet and insulation from behind the seats and the smell is getting worse. Undid all the bolts and was faced with a brand new very sealed membrane, removed and right hand side under the tank wet with fuel.

The upside, the very nice man had made sure it would be safe because he had removed both of the floor bungs so that the petrol which leaked could drain away, (I suspect this is why reversing increased the smell)

I now hav a nearly full fuel tank with a leak, i know not where. Drivers side of the tank and floor look completely dusty and dry even behind, well as much as I can see. Pipes at the top all look well sealed, when the fuel pump pressurises, after ignition on it runs then stops as it achieves pressure before engine start.

Logically I should use as much of the petrol as possible which will take a week or so of driving, in not the safest conditions. then take out the tank and identify what needs replacing.

Unless anyone has had this before and has an idea what the leak is, in which case I will be able to get the parts ordered (probably ebay) and get on with the repair.

Any constructive suggestions welcome.

Nightmare!
I can only suggest checking for the leak every day as the level drops in the tank. if it stops you've found the level of the leak.:shrug:

syphonning the petrol out into petrol cans might be safer? :dry:
We had issues with strong petrol smells, but ours turned out to be a badly bodged 'fix' on the sender unit

yours sounds like more of a definite leak of liquid though - hope you soon find out the cause

just a thought...no-one's done anything daft like drill into the tank whilst fitting speakers or something have they? It has been done before!

I would advise getting your tank drained, you've already met with the hard work of taking everything out to get access to the tank itself. The drivers side is a different depth to the passenger side so most of your fuel will be behind your passenger. It sounds like either your tank has failed possibly on a seam, or as Birks says "something daft" has drilled through it. Don't ask me how I know about fuel smells - I am the "something daft" Birks refers too
The seller did you no favours and I'd be a bit cross with him for saying it's sorted, it seems he's put your safety at risk with a quick cover up.
If you can drain it you may be able to get it repaired but I'd go for a replacement (I got one for £20 from MGFnTFbitz + delivery of course to Cornwall. There is clearly a leak and only getting the tank out will reveal it, I assume the sender unit screwed to the top is all dry? Took me 4hrs to get tank out 1/4 full and replace with lots of sweary moments. If you attempt this with fuel in almost full you won't achieve it as the tank will be swollen and it's a small gap!

Good luck mate.

Found my smell of petrol it was a very small leak on the fuel filter

its unlikley to be the fuel tank. best bet is to place tissue paper around every joint,and run for a couple of minutes.
then hopefully the tissue paper will be damp.there are loads of o rings,pipes,connections all of them can cause an issue/
a common problem is the fuel rail where the injectors feed from,these are plastic and can split.
fuel pump gasket is another favorite.

Thank you for all the constructive comments. I will drain tomorrow as much as possible then try to isolate where the leak is. The tissue paper seems as though it may work, thank you for that. Tank straps are loose, the left hand one has no rubber behind it and the right hand (drivers side) has only half the rubber. So some chafing already evident. But confident this is not the source of the current leak.
I will update tomorrow or Sunday and if its gory I will upload pictures. There will be blood, there always is.

Good luck mate

They Cheated.

If you are going to bodge a fix then be fair and make it obvious. The sender unit was the same as yours singing bush except the fix was done with white resin so does not at first show up. I think without the tissue paper test I would have taken out the tank and still been none the wiser.
Its leaking around the return, means I will have to replace the sender and wait for it to arrive but as long as I can do that through the top I can rebuild the interior. I have attached a pic and you can see the areas of filler in between the pipes. Thank you to all for your assistance. (May need more yet)

Well done for finding it, its also good to see that the component that failed was a BMW item :yesnod: (not that I'm bitter or anything :lol: )sorry ex employee :broon:

Well that's a lot easier than replacing the tank! :yesnod:

Thats great news mate, well done finding it. It's was Birks sender unit not mine though, I was the tool that drilled thru the tank :blush: - very shoddy that they chose to repair it and not tell you how, still at least your peace of mind will return now