Help from members of 230sls smell of fuel

[Merc_Girl]

Hi folks

Hoping our illustrious group may be able to help/advise

So, when I fill up Bessy, she is the early 230 SL with spare tyre mounted vertically, there is a strong smell of fuel.

I was told that this is ‘normal’ if you fill them up?!? Find this somewhat hard to believe as I’m sure I would have read that somewhere. It has therefore been advised only to fill her 3/4 full otherwise fumes comes out of the breather valve?

Dos this sound right?

I don’t really only want 3/4 tank to be considered as the maximum to fill the tank, considering the tank is fairly small anyway

Can anyone advise what needs to be looked at or is there something else that can be done to overcome this issue?

Thanks in advance
Katie

[Cees Klumper]

Others will weigh in here, but on my 280 there is definitely no fuel smell when I fill it to the brim. Seems highly unlikely to me that a fuel smell would be 'normal' when filling up to the max in a 230 SL. More likely something needs replacing.

[franjo_66]

Hi Katie

I also had this same issue on my 230SL (1965). It was an easy fix. Unblocked the vent that pops out at rear right hand side (near rear muffler). And then I disconnected the hoses to the vent cannister in trunk. Blew compressed air through them. Checked for any holes/deterioration - all hoses good. Reassembled hoses. No more fuel smell after filling up tank !

[Bonnyboy]

I have been chasing the gas smell in my trunk as well -  its getting better - I found that the vent hoses in the trunk seemed to be permeating the gas smell so I replaced them and it helped.

Before that I found the top of my tank had a few rust holes that was causing fumes and then the gasket where the fuel sending unit is was smelly -  I took a piece of garden hose and did sniff tests to find the vent hoses and the sending unit gasket.   the holes in the petrol tank were cut out in a section and a new plate brazed in so the tank doesn't smell anymore (radiator shop did that after they boiled the tank and protected the flower pot and cleaned it).   The rust came from above rather than from within so thaht is why the radiator shop decided to keep the tank.   (I have since obtained a spare tank just in case)


 

[Pawel66]

I think there is a pattern emerging here:
1. It is not normal that it smells fuel in the trunk regardless of how full the tank is.
2. The usual suspects (also in my case) are
- vent lines not tight
- vent lines stuck (including the one with the cone)
- cone missing or misplaced (I am serious, there is no vacuum created if it is the case)
- evaporation tank connections not tight
- evaporation tank clogged
- fuel level sensor gasket not tight
- tank not tight (hopefully not the case)

All easy to check and not difficult to get to.

[Merc_Girl]

Thanks everyone for your prompt responses 😁

I will start my investigations

X

[Benz Dr.]

I have been chasing the gas smell in my trunk as well -  its getting better - I found that the vent hoses in the trunk seemed to be permeating the gas smell so I replaced them and it helped.

Before that I found the top of my tank had a few rust holes that was causing fumes and then the gasket where the fuel sending unit is was smelly -  I took a piece of garden hose and did sniff tests to find the vent hoses and the sending unit gasket.   the holes in the petrol tank were cut out in a section and a new plate brazed in so the tank doesn't smell anymore (radiator shop did that after they boiled the tank and removed the flower pot to clean it).   The rust came from above rather than from within so that is why the radiator shop decided to keep the tank.   (I have since obtained a spare tank just in case)

I never thought that you could remove the flower pot. Maybe you can tell us how they did that.

[Benz280]

As told by Pawel66, I just had the same issues. Turned out to be lose line connections.
Also blew some air into each line ( Manual Style ) to make sure they were not clogged .
Smell now gone

[Bonnyboy]

I think I was incorrect in my comments -  I don't they actually removed the flower pot -  I don't know exactly what he did so it didn't disolve with the chemicals he put in the tank but he was located right behind the mercedes shop so he was familiar with it. 

[JamesL]

Katie, I’ve had a similar issue and always assumed it was the expansion tank on the side wall of the boot (trunk)

I finally got fed up enough to dig around some more and after a trip through the tech manual and a post from Naj (rip) from waaaaay back, I undid the 10 screws around the filler cowling (inside the trunk) and found the pipes not clamped. The flex pipes had a strong fuel smell (unlike the expansion tank ones).
Hopefully 4 clamps on new hose has fixed the issue
(Picture taken from above)

[Paul & Dolly]

Katie

I concurr with James, in my case the pipes were incorrectly sized, and the clamps missing.
I replaced the hoses with correct fuel grade hose, and fitted new clamps, and the problem was solved.

Paul