exhaust smell

[ostapcik]

We recently bought this 1986 535i off a museum floor where it had been sitting for about 3 years. Naturally there were several repairs required. One that is stumping me is that the interior of the car smells of exhaust. I am not sure even where to begin to look. The car is a 5 speed with a short shift kit and an ansa exhaust. Otherwise it seems quite stock.

Is there a charcoal canister on this car? Maybe someone could direct me to the right place in the Bently manual? Any ideas would be appreciated.

[znebto]

you might want to check the vent covers under your hood as lately discussed here (viewtopic.php?p=1538650 - sadly the Pictures died somehow)
But as also already mentioned there, the chances that there's just an exhaust leak are quite high, so maybe start there 

[Mike W.]

Hmmm, I swear I already responded to this, but it's not here.

Anyway, here we go. Yes, there should be a charcoal canister, IIRC it lives under the battery.

But gas and exhaust are to me, very different odors. If you're smelling exhaust I'd look at the exhaust manifold to downpipe gaskets. There are at least 2 different gaskets and one IMO is not good, a solid metal gasket with little if any compressability. It's the dealer one. Might be ok on brand new perfectly machined parts, but not on 40 year old stuff. I was chasing a leak on a Bavaria long ago and while I don't recommend it, the only way I could find it was by sticking my hand on the joint on a cold start, briefly, before it warmed up. I could then feel the leaking gasses. Moving quickly I might add.

The good gasket.



The bad gasket. Solid Steel. Not very conformable.

[Mashford]

I located an exhaust leak where the exhaust pipe meets the manifold. The gasket is leaking. Are there any posts or videos anyone knows of coming in from ahove and replacing the gasket? I’m just not sure how difficult that is and I’m working in the driveway. The bolts look fairly corroded so I imagine they’re gonna be tough to knock loose. Thanks! 

[Mike W.]

Not sure about doing it from above, but very doable from below. Lots of extensions, a U joint and a 6 point, 14MM socket. If the hanger for the exhaust from the tranny is still in place you'll have to unbolt it from that. Stock IIRC they were 14MM nuts, but some newer ones are 15MM and very old ones were 17MM. But you really want a 6 point socket, 12 points are good at rounding them off. And you want new, copperlock nuts. I would emphatically do both gaskets for both manifolds and you might be juggling a bit trying to keep the gasket in place for both, while getting the cat/downpipes up there.

Technical difficulty is low. PITA factor medium low. Just work laying on your back under the car.

Jack it up, jackstands, all that. Laying on your back with crap falling in your eyes unless your car is meticulously clean like say one of TIG's cars.

[Mashford]

Thanks, Mike!