Smell of gasoline in trunk

[TR]

From time to time I have noticed a strong smell of gasoline when I open the trunk lid.  Not always and not the same strength of odor every time.

Have others noticed this?  Any ideas what might be causing it, and how to cure it?

My guess is that there might be a small leak in a fuel line.  Perhaps it depends on tank level, when I last filled it up, whatever.  But that odor of gas comes and goes and I've never been able to correlate to any particular action or circumstance.

Tom in Boise
'71 280SL Signal-Red w/lt. tan leather

[Cees Klumper]

Yes this is a common ailment. It's usually caused by cracked or loose fuel lines going to the small plastic overflow tank that's (AFAIK always) situated at the right-hand side rear quarter panel inside the trunk. Probably if you do a search on "overflow tank" you will come up with a deluge of information on the how to's, why's and what's. Should be an easy fix if the the problem is 'standard'.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[n/a]

I had the same problem when I first got my '71.  Cees is right - it turned out to be the fuel expansion tank, which sits in the left side of the trunk.  I had it replaced and the fuel lines that go to and from the tank as well, and now things run like solid gold.  There are two sizes of expansion tanks - the '71 requires the larger one.  I got mine from the Mercedes classic center for about $80.

Good luck,

Joe

[rwmastel]

Along with "overflow tank", search using "fuel odor" or "trunk odor". There is LOTS to be found using the search.

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[TR]

Guys -- Thanks very much.  Your advice was helpful and all the parts are on order.  Just to be on the safe side we're going to replace practically everything mentioned in those various threads.

Tom in Boise

[merrill]

hello,
I had a similar situation, always a slight smell of gas.
When I replaced the fuel sending unit gasket i found that the gasket was deterioriated and leaking just slightly on top of the tank

something else to check.
matt

[TR]

Matt -- Thanks.  Yes, we'll be replacing that seal too.  It is only a few bucks.  My philosphy is to do it all.  The parts mentioned in those threads don't add up to many $.  Cheaper and more comforting to just get it all done at once I believe.  The only piece that had any cost associated with it was the plastic overflow tank itself...list was somewhere around $80.

Thanks again guys.

Tom in Boise

[Cees Klumper]

Tom - the plastic tank itself is easy to check for leaks and MOST likely will not have a leak - unless it's been improperly handled somehow, I think it is unlikely it will ever develop a leak 'by itself'.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[TR]

Cees -- I have no doubt you're correct.  But as I plan to drive the car for at least another 30 years I feel good about replacing it just for the comfort factor.

Tom in Boise

[mdsalemi]

Tom,

DON'T replace the fuel expansion tank unless you need to.  The "new" ones are all one-piece units with 3 plastic fuel lines that go to the vent parts on the tank.  The stock, original ones had brass pipe nipples and allowed you to use fuel line and steel fuel pipe.  The plastic lines can get easily crushed.  Been there, done that.  I'm back to the original.

Michael Salemi
1969 280SL
Signal Red w/Black Leather
Restored

[TR]

Michael -- That's very good to know.  Thank you.

All the bits & pieces are being shipped here.  When they arrive I'll be sure the mechanic is aware of what you've been through.  After looking everything over we can always return that replacement expansion tank.

Tks again.

Tom in Boise

[69280sl]

I am trying to get rid of a gasoline smell in the trunk, following the excellent suggestions of this thread.
Question; My three flexible lines have hose clamps at the top where they connect to the vapor tank, but not at the lower ends where they are slipped over the metallic lines.
Is this correct, or am I missing 3 clamps?

Thanks

Gus
68 280sl
Signal red/beige


inspectorgm

68 280sl, signal red/ beige/black softtop

[rmmchl]

unscrew the black metal round type object in the trunk. There are fuel lines that come from the gas tank to connect here to the overflow. The leak might be here. I had my gas tank removed and they forgot to connect this. This shroud cover must be removed before you can connect these lines properly.

[Jonny B]

When I replaced the hoses on my car, I did not put clamps (and there were none there) for the lower fittings (the ones behind the metal cover) This is not a high pressure set up, and a tight slip fit should not be a problem. Do check that all the hoses and lines are clear and free of build up (this was a problem with the metal lines on my car as well).

Jonny B
1967 250SL Auto

[k]

I just did this b/c of fumes in trunk & cabin, and the results are truly amazing.

Zero fumes!

I used to think it was everything from the leaking gas cap, to over-rich idle to oil burning

You unscrew inner filler tube cover.

I had one braided tube which was soaking wet; it was causing all the fumes.

-Remove 4 braided rubber lines; (2) from tank to metal lines along back of trunk;
-then the (2) rubber lines coming back from overflow back to metal lines;
-You get 3/16 in. rubber fuel hose from NAPA/Autozone, Pepboys.
-8 hose clamps

Also: K&K sells the foam donut that fits between main tank and trunk floor; and a new inner filler tube cover for $38 (mine was distorted), which you can seal with a sealant or gasket; so I now have airtight seal b/w trunk and outside.

Total time: 30 min.

If you have any faint odor of any kind do this today !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[JamesL]

I love this place

Car is just back from a few days with Stick but when it went in I forgot to mention the pong of fuel in the car, and remembered on my way home.
Quick search on here and half an hour outside I have

• re-affixed my hardboard panel to the side of the spare wheel (tape...)
• re-affixed the expansion tank to the hardboard (clip, with tape ) so it's now in the position it's meant to be in rather than resting on the spare!
• secured the pipes from the bottom of the expansion tank. The middle one was loose and on moving the tank, fuel leaked into the boot.

Just been out for a wee spin and pong-gone!
Yay

[mmizesko]

Just had this problem this spring.  What amazes me is that a 10 year post and thread is just as vital today as it was then, and is resurrected from time to time and made new again.  Where else but SL113.org. I hope this information endures to many generations of Pagoda owners in the future.  Peter, you'll have to stay alive until then.  Maybe we can prop you up and paint you like Lenin.

Mike Mizesko
Columbus, OH

[Paul & Dolly]

Vent Connections:

I discovered my vent lines were very loosly connected by 3/16" Fuel hose, without clips on the tank end, and with clips on the "Box" end.

The tank tails are 5mm, and the Box has two connections of 5mm for the tank, and one of 6mm for the vent to the Funny Funnel Device that hangs under the car by the exhaust.

I have ordered some 4.5mm (11/64") braided Fuel pipe, ( 4.5mm I/D and 9.5mm O/D) and 9 mm spring clips.
SLS spec indicates 4.5mm and the 3/16 that was fitted to mine seems too big to me, unless 8 clips are used.

Has anyone any thoughts on just connecting the Box to the tank with only Braided Fuel pipe, thus eliminating the steel pipes ?
This would only entail two clips per pipe, as opposed to 4 clips per pipe.


Thanks for any input

Paul

[Jonny B]

Using braided fuel lines will present a bit of a fit issue when you put the cover piece (over the gas tank neck in the trunk) back in place. The steel lines fit thru there very closely and the extra diameter of the fuel lines will not.