C36 AMG, C43 AMG (W202) 1995 - 2000

Battery vent question..

Old Mar 12, 2015 | 11:55 AM
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1999 C43
Battery vent question..

Hello! I went to change the battery in my 99' C43 and noticed that the vent hose connected to the old battery wasn't attached to the car anywhere. The previous owner just had the tube hang down from the top of the battery down to the tray - not connecting to the outside of the car..

My question is.. where this tube is supposed to vent out to?? I don't see any way for this tube to reach out the car. (Maybe they used a wrong tube?)

Also, is it absolutely necessary to vent the battery? It seems that the previous owner didn't mind it not venting.

Thanks in advance!!
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Old Mar 12, 2015 | 01:20 PM
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hey

infront of the battery is a black box with fuses inside next to this box on the left side, there's a black rubber plug, you must push the plastic tube through this rubber plug, the tube is seen in front of the rear axle, standing from behind of the car.

ventilation is a good thing to have otherwise it will leak acid from battery on your battery tray, it will screw up the paint from acid
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Old Mar 12, 2015 | 06:29 PM
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1999 C43
Thanks a million! Haha I would have never found it!
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Old Mar 13, 2015 | 03:37 AM
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12' W204 C63 AMG coupe "T-Rex", 12' W451 Smart Fortwo Pulse (99' W202 C43 AMG + Ultima Can-Am sold)
Both the c43 and my other w202 have some acid corrosion on the battery tray even with the vent pipe correctly installed. Guess the vent pipe is not sufficient to eliminate all the acid gasses.
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Old Mar 13, 2015 | 03:42 AM
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^+1^,

don't think that vent hose can deal with acid demon..!,,

Why not go with AGM/silver technology..

ZAYED,,
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Old Mar 13, 2015 | 07:33 AM
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The purpose of the vent hose is to disperse hydrogen gas, which is a byproduct of charging the battery, to the outside. If it accumulates in the trunk it can cause an explosion when you open the trunk (the spark comes from the truck light switch contacts). There was a recall/campaign on the W202 regarding this issue.
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Old Mar 13, 2015 | 07:46 AM
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factory MB batteries has openings on each side for drain hose.
my battery has it.

if you connect hose plug to one side of battery, then you'd better plug the other side to prevent acid leaking out on battery tray.
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Old Mar 13, 2015 | 05:27 PM
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I glued the second hole opposite the one with the vent hose.
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Old Mar 16, 2015 | 11:31 PM
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1998 c43 amg
Originally Posted by vinceC
The purpose of the vent hose is to disperse hydrogen gas, which is a byproduct of charging the battery, to the outside. If it accumulates in the trunk it can cause an explosion when you open the trunk (the spark comes from the truck light switch contacts). There was a recall/campaign on the W202 regarding this issue.
This is absolutely the correct answer
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