Fuel overflowing

[n/a]

Hi Guys

I took my 230 SL for a spin today and when I returned, petrol was leaking out of the overflow pipe onto the garage floor. There was also a lot of gurgling and percolating sounds coming from the tank. It was a very hot day (just under 100 F in the old scale) and the tank was close to full. This has never happened before. Should the petrol cap (original) be vented? There was a big release of fumes when I removed it.

Any suggestions would be much appreciated.

Mark

1965 230 SL light blue, auto, RHD

[Richard Madison]

Mark:

Gas caps have been discussed before in several messages, also   overflowing petrol.

Use the Search for "gas cap",  can also try a "petrol" to see what else comes up.

Richard M

[hands_aus]

For 230 sls and early 250 sls, I believe that when the main tank is really full the little expansion tank fills up too. However it has only a limited capacity of about 500ml.
The excess fuel just escapes through the overflow pipe as it is supposed to.
The 280 sls  have a closed system with a return hose to the inlet manifold.
From what I have read, the fuel cap should NOT be ventilated.
I think the 230 sl fuel system breathes through the expansion tank and overflow to the atmosphere.

Bob (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[ted280sl]

Mark,
  The gas caps are not vented. Bob describes the fuel system of your car accurately. Excess fuel will flow through the overflow pipe if you overfill the tank. The solution is to not overfill the tank. With the price of gasoline these days I believe it is a very sensible solution.
regards,
Ted

[J. Huber]

It might be a good idea to check the small fuel lines that attach to the ventilation tank. You need to remove the roundish metal cover inside the trunk to see them.

James
63 230SL

[n/a]

Thanks for your input everyone. I'll take a look to make sure all is as described.

Mark

1965 230 SL light blue, auto, RHD

[Benz Dr.]

Late cars are vented into the engine. The fumes are then drawn out through the  tube on the valve cover and go into the intake at the air controller housing.  This seems like a trange way to do things but I suppose the engine could hold a fair amount of fumes without releasing anything into the atmosphere. 107 cars are set up in a similar fashion so I have to believe it's safe to do so.

Daniel G Caron