SL/R129: Battery Vent Holes
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Super Member
Joined: Aug 2005
Posts: 591
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From: Covington, WA
'96 SL600, '05 S55 AMG, '06 C230
Battery Vent Holes
Something to keep an eye out for if you get a replacement battery from MB... Replaced the battery a few years back in my SL600 using a battery from an MB dealer. The car, when new, was delivered with a sealed battery; no battery vent mechanism was designed into the car. The replacement MB battery was not sealed and had vent holes, fore and aft. So when I installed the replacement battery – without fully inspecting the battery – there was no vent hardware to install. Unbeknownst to me and over time, the battery leaked acid out the vent holes; more out the rear (hard acceleration) than the front. (It’s a V12… what do you expect?) So after a few years, I began getting corrosion in the battery compartment.
In my R129, it was easy to simply add a plastic line through the forward drain hole and connect it to the rear battery vent hole. I chose the rear vent hole since it would be easier to inspect the plastic line. You'll need a small plastic plug for the forward vent hole, and small plastic elbow for the rear vent hole, and a length of clear plastic tubing.
Obviously, if you have a sealed battery installed, this is not a problem. But MB batteries can be delivered as vented. Just an FYI.
Cheers,
Jeff
In my R129, it was easy to simply add a plastic line through the forward drain hole and connect it to the rear battery vent hole. I chose the rear vent hole since it would be easier to inspect the plastic line. You'll need a small plastic plug for the forward vent hole, and small plastic elbow for the rear vent hole, and a length of clear plastic tubing.
Obviously, if you have a sealed battery installed, this is not a problem. But MB batteries can be delivered as vented. Just an FYI.
Cheers,
Jeff
