This may seem crazy but my mini stinks of fuel when sitting in the garage. I’ve checked the whole system from tank to carbi and cannot find any signs of a leak, no damp spots etc, but the smell is really strong and does seem to be coming from the rear of the car. But I’ve checked it out at twice and just can’t find anything. Any suggestions?

Had a similar problem with our Cooper S and I found I had vented lockable caps on tanks. On the S the tanks are vented through tubes from the top of the tanks through the boot and the floor, so I replaced the caps with non-vented lockable caps, cleaned up the top of the tank neck to ensure I had a flat surface around the edge of the tank opening so the cap seals would seal and problem solved. While I was waiting for the lockable non-vented petrol caps to arrive, I put some old caps on and one smelt, but the other didn't. Swopped caps and same one still smelt. It appeared the cork seal was not fitting properly. So you could have the wrong petrol cap, the entrance of the tank may not be straight or the seal on your cap may not be still serviceable.

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Mini Cooper S Mk 2, 1970,
Mini van 1970 with side windows now converted to 4 seater traveller

thank you so much, I hadn’t even given the cap a thought! Yes it is definitely a vented locking cap so will have to hunt through my spares and see if I can find the old cap. Hopefully problem solved.

And just realised I posted this in the wrong section