hose located in battery well on W124 E420
 

where the positive terminal line is, I see this rubber hose, about 1cm to 1.5cm in diameter...does it stick into the hole I see close to it on the chassis? what exactly is its purpose? thanx...

i am not sure what hole you see on the chissis but if that hole leads to the outside of the car, you DEFINITELY want to connect it.

As the engine run, it charges the battery. When battery is being charged, it creates hydrogen gas. The purpose of the hose is to let the hydrogen gas escape from the car. If the hose is not connected, the gas will built-up around the area. A good dose of hydrogen gas plus a spark, a light from someone smoking maybe, may prove to be too james bond for you. Don't forget your battery is under the rear seat.

Likeihood is not that high but its a risk we all want to mitigate. I myself lost that hose but my battery is in the boot. just find the right hole and plug it in!

cheers

Youd actually be supprised to know that Hydrogen gas rises so quickly that it is very unlikely to happen.

You are right about the hose.

this hose does not seem to serve the purpose of venting hydrogen out of the battery housing....the hose seems to lead INTO the battery housing from somewhere in the rear of the cabin...I see it exiting from the same place as the positive terminal...I see a hole near the hose though in the chassis...next to the vents that are covered by the side of the rear bumper...the rubber hose is around the same diameter, and the hose is cut slanted...basically, I dunno where the hose is coming from...and where it should connect to in the battery well...I assume that hole...but I do not know its purpose...it is it just suppose to hang loose in the battery well area to serve as venting, I wonder where the exit is...I tried to pry at the carpeting to get a better look, but kinda difficult...

ohhh, I think that goes from where you fill up your car for overflow behind the positive terminal, and then through the rear frame rails, then out through the right rear side of the subframe.

To let gas go to the ground when you top off the tank.