Smelling Gas

[Cooper24]

I have a 93 525 with about 160k. Every winter it seems as though I can smell gas in the cabin of the car when I start using the heater. I can not smell gas during the summer times when I am using the AC. I thought about a few things to explain this such as in the summer I typically have the recirculation on and in the winter I don't. Anyway, is this a common problem? Where should I start to look?

Thanks

[Kalevera]

Charcoal canisters are known to go bad, but I believe they typically go south after ~ 20 years of use/big mileage.

Gas leaks can be difficult to find; the car has to be gone over carefully, all fuel lines have to be inspected, as well as the evap system. I follow my nose -- you'll be able to smell the leak in the general vicinity. If the car has been beat up, the tank could have a hole in it at a seam or up top due to rust. You'd smell such a leak outside of the car. I've never seen one leak on an E34, although I see it all the time on E30s.

One thing to do is pull the fuel pump access cover in the trunk (black plate, to the right of the spare tire well, under the carpet and insulating pad) and inspect the lines. It's highly unlikely that the culprit will be in there...probably a bad rubber line up by the blower motor in the engine bay...but it never hurts to look.

You should be happy the car hasn't blown up on you yet...smelling gas every winter and nothing's been done about it yet? sheesh.


best, whit

[shogun]

the complete exchange of all fuel lines as well as the evap system. On a 12 cylinder engine room not the nicest job, altough I have many top parts of the engine out as you know.
Yoy cannot believe what I found there on the fuel hoses and evaop system. evap system hoses were (the car is from 1990) so brittle, they broke like glass tubes into pieces. The fuel hoses were 'stone-hard'.
Speaking about a V12 engine room, I can only recommends to replace first of all the 2 small about 10 cm fuel pressure hoses which come up at the firewall driver site out of the wheel frame under the fender. These short enforced/braided hoses connect the fuel lines from the 2 fuel pumps coming from the back of the car and the fuel lines going to the engine under the engine sound absorbtion cover. These rubber hoses are very important, as they are the flexible joint between the fixed fuel hoses on the chassis and the fixed fuel hoses on the engine (flexible mounted on the rubber mounts), which of course moves when starting and accellerating/deaccell...
So these tiny things have a lot of moving over the years and they are usually the first thing to break.
It took us a full day with 2 persons (with long coffee breaks of course ;) ) to replace the hoses all. Very difficult on a 750 because of the little space.
Ordered all the hoses from Autohaus Arizona, as one meter costs here about 60 $ in Japan.
I will cover these OEM hoses now in some areas with cut off (like a spiral) special high temp resistant silicone hoses as protection against engine heat. Not sure if it works.