Well being under the drivers seat and the car being French it's probably a "gas" collector accessory if you catch my drift Clare and yours is overflowing and requires some release. Either that or it's a propellant for the ejector seat leaking.

Well being under the drivers seat and the car being French it's probably a "gas" collector accessory if you catch my drift Clare and yours is overflowing and requires some release. Either that or it's a propellant for the ejector seat leaking.

"Under the rear seat, behind the driver."

French drivers drive from the rear seat now?

Well being under the drivers seat and the car being French it's probably a "gas" collector accessory if you catch my drift Clare and yours is overflowing and requires some release. Either that or it's a propellant for the ejector seat leaking.

"Under the rear seat, behind the driver."

French drivers drive from the rear seat now?

French Car + French driver they would not be sitting on the right anyway.......... so you would need to ask a french driver what it is under the rear seat of the passenger side..

May not be it, but somehow believe they had an inspection cover under the rear seat, you could get at the petrol tank. it is many years ago that I worked in France and the Boss had the sporty Mi-16 model 405

Well being under the drivers seat and the car being French it's probably a "gas" collector accessory if you catch my drift Clare and yours is overflowing and requires some release. Either that or it's a propellant for the ejector seat leaking.

"Under the rear seat, behind the driver."

French drivers drive from the rear seat now?

Geeezzz seriously??...

you have probably fixed it by now..

but first thing to do is..

1. is it engine oil smell? or fuel smell? if you're not sure.. open ur fuel cap and take a sniff. if it smells the same as in the car.. then it is a fuel leak... otherwise it is most likely leak caused by engine oil leak

if engine oil, it may also come in through the firewall, or aircon ducts. make sure u check the level of engine oil by using the dip stick before driving... leaks un checked may ruin the entire engine.. (might as well buy a new car!!! depending on age/purchase price).

if fuel, it could be fuel lines, injectors, hoses and even the fuel pump under rear seats.. for older cars that may have been left for long periods without much fuel in the tank. it can also be fuel tank seals drying up.. not too expensive for the seals.

exhaust leaks may be easy to fix depending if it is a simple connector part.. or.. rust.. which will be.. tough.

Peugeot 405's are designed by Pinifarina. The design is timeless. Those cars are much more fun to drive, than any Vios, City or similar.

Anyway, take out your lower back seat and than you'll see a cover, where the fuelpump and gasoline sensor unit is placed underneath. Remove the upper cover and check the gasket of the fuelpump and gasoline sensor unit. That's the one usually leaking. Even a small crack in the gasket can create already a bad smell in the car.

Thanks Rt85, Stingray, yes its definitely fuel, not engine oil, and no I haven't fixed it, it just happens so rarely and intermittently that I've just ignored it. It seems to happen only when its cold out.

Interestingly this problem as well as the low idle problem which had been annoying me have slowly gotten better (happened less) with time & driving.. Which certainly seems strange to me!

I had an old car.  fairly noticeable smell in cabin.  Fuel tank needed a patch up. Not expensive. 

8 hours ago, stud858 said:

I had an old car.  fairly noticeable smell in cabin.  Fuel tank needed a patch up. Not expensive. 

Try Araldite ... not exactly a good idea to try welding unless you fill the tank full of water first... even then stand well back ?,