What is this - Fuel Vent

[Garry]

I went and had a look at a 230 Sl for another member here and noticed this hanging below the rear bumper.

What is it, some sort of vent for the tank?

Garry

[DaveB]

Yes, fuel tank vent via the canister in the boot. Doesn't seem sensible to vent fuel vapour next to the exhaust but I haven't heard of any disasters.

[Richard Madison]

Here's a photo of a "Fume Tank" on the right trunk (boot) wall. This style fume collector was replaced by a larger fume tank found on later cars which was usually mounted on the left trunk wall. The larger collector did not have the outside bell shaped vent.

The tubing along the right side of the tank that disappears under the trunk mat is the one going to the outside vent.

Also a photo of a similar vent on Euro version car.

I have seen this style vent on several Euro cars. Don't recall seeing one on a US Version car.

Richard M, NYC

[Garry]

Thanks Dave and Richard, I thought that is what it was but I had not seen it before.
Garry

[thelews]

250 SL USA

[mdsalemi]

It's actually not just a "fume tank" but a "fuel overflow tank".  If the tank is full, and the weather warm, the fuel will expand into that tank and then as things cool down, will drain back in to the tank.  If it exceeds capacity, the excess fuel will drip out the funnel shaped thing at the back.

I cut one open once--nothing inside but three fittings to accept the fuel.

[Dave]

John
Your underside looks better than a new car.  Did you disassemble and powdercoat everything?  I hope you have a mirrored garage floor.  What a view!

[thelews]

Can't take credit, previous owner of 37 years.  He cosmetically reconditioned components under the car as he serviced them for maintenance or rebuild.  The car has over 150K miles on it.  Nothing is powdercoated.  He sourced factory type paint and sprayed components himself.  Very durable finish.  I just did my annual oil change, grease and undercarriage cleaning!

I see you're in Chicago.  Have you been to one of Black Forest's spring MBCA tech events?  www.blackforestllc.com  You would have seen the car there.

[Garry]

I am surprised that they would put it so near the exhaust.

John,

Am also bit surprised that you appear to have left some stones in your tire treads.  Bit out of character for the car.  
That undercarriage is so great. Between you and the other John '49er' as original owner the two cars are such a great resource material for others.

Garry