I had my battery out and noticed this part sitting under the black box adjacent to where the battery sits.

 

I believe it sits on the positive receptacle of your battery.

 

how funny, I found that under my hood today also.

 

Push on battery vent....Squirrel Crusher

 

As stated by the Squirrel, it is the battery vent and goes into a hole on the top of the front end of the battery. It catches any moisture that comes out and lets it evaporate.
Edit. There is a hole at the positive end on my battery as well and it is plugged and has no vent.
It has nothing to do with the terminals.

 

It attaches to the Posittive terminal of the original battery. I just replaced mine and they did not offer the same piece of plastic. I have no idea what it's function is!

 

Be very careful of who's advise you take. The part you have in your hand plugs into the end of the battery, on the negative side.....photo below:

 

I don't have one!!!!! Bought my XF 6 weeks ago without one. Am I in trouble now???!!!!!

Where can I buy one?

Monty

 

Hmmm Mercedes logo...
Hmmm Part Number...

Hmmm... Search A0005410063

https://www.crossfireforum.org/forum...p-id-part.html

 

Sweet! Thanks! I had a feeling it had something to do with the battery.

 

It sticks in the end of the battery and catches the overflow water if there is any.

As you look at the battery from the passenger side ,this plugs in to the right top side of the battery where you'll see a hole the tab sticks in.

Hope this helps.

Dave Woolage _/)***

 

Do you have the hole in your battery? This is the only time I have seen one on a battery. If you have the OEM battery like the photo shows then yes you should have one. If you do not have one the battery acid will drop onto the battery seating and start to corrode the steel. No hole ... no problem.

 

believe it or not, that most likely is your batteries flash arrester. we put them in our batteries (die-hard, odyessy, stinger, SBS 145s, etc) but the ones we use are little styrofoam pellets or flat disc that sit beneath the top valve cover label. it appears to have the same function, if in case it flames out(?) it keeps it from spreading. If anyone doesnt have one I wouldnt worry all that much about it

 

Went out and popped it right into place. Thanks!