Couples days ago my wife's 99 E320 wagon started doing crazy things: it rides alright, but once we park it and lock the door, several seconds later all four windows,and sunroof open themselves and all locks pop up! It was like a spirit inside the car doing the trick! Later I found there was about half inch deep of water inside the battery housing under passenger seat.

Where did the water come from? I sent the car to a neighbor mechanic, and for two days he could not locate the source. Spent $600 to replace control module.

To test if it was leak from sunroof or window, I cleaned and dried the housing completely. The car is always parked inside garage. The next day, hot sunny day, after driving it from home to work, I opened the passenger seat... and voila! Water there again! [:@]

There is a little tube hanging next to the battery, and it did not connect to anything. I am wondering should it be draining water (from where?) to outside.

Any idea?

Guang

 

Sure its not battery acid rather than water.

The little tube is a tube to pipe away hydrogen and acid spray from the battery to outside or otherwise the possibilty of a big "Boom!" especially since battery is in the passenger compartment on E Class.

If it is acid then maybe the battery is overcharging.

Stuart.

 

I am sure it is clean water, not acid ... I actually tasted it[8D]

I am sure the water is not from outside leaking or something. This morning before I drove it, the housing was dry. And today is a hot sunny day in Houston. When I arrived at office and look at the housing... water again!

My gut feeling tell me the only place that "generates" clean water on a sunny day is the A/C condensing coil. But why the condensing water would end up in battery housing?

Or does E320 has other water generation potentials?

Thanks,
Guang

 

Hi Guang,

In today's litigious world I didn't dare suggest tasting it but that is an appropriate test.
The difference between water and acid will be all too obvious.
Anyway water is better for the electrics and bodywork than acid!

Does your wagon have independent rear air con? Not just the vents but also the evaporator. Not sure if itwas an option in 99.

I also can't think of anything else that might "generate" water other than the exhaust and possibly the rear screen wash.
Where is your rear screen bottle located. Under the hood or the sides of the load space?

How about using talcum powder or similar over the sides of the battery box.....this will increase the chance of seeing the ingress route and therefore locate the source.

Good hunting!

Stuart.