Can't figure out where this vacuum tube connects...

I found the same tube yesterday while reconnecting my battery and had the same questions. Anyone??

 

is it the vent tube that should be connected to your battery?
rgds,
Vincenzo

 

The original VR760 FIAMM battery and the common Interstate MTP-91 replacement are vented through a tube to prevent a build-up of sulphuric acid fumes in the battery compartment.

Unvented batteries have caused some owners problems, big time, with corrosion.

Taz
Terry Phillips

 

not to mention the hydrogen that is venting all around the electrical gear under your dash.
rgds,
Vincenzo
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That's the battery vent tube indeed folks. Do yourselves a favor and buy an AGM (gel) battery, which is the only truly sealed battery. Maintenance free 'sealed' wet-cell batteries are not sealed, so DO NOT get one of those. Like Taz said, both the stock Fiamm and Interstate MTP-91 have a vent port, but at least on the MTP-91, the vent is not going to prevent a leak (don't ask me how I know that), since the shape of the vent port is ovoid, not round. Fortunately, I checked the car in and out right after I got it, and my stomach sank to the floor when I saw the royal acid (foam) mess there was in there. Fortunately, no damage other than the metal tray, and just a bit of the carpeting at the edge, but that's well out of sight, inside the battery compartment. After hours of work, looks like new now. A wet cell battery has no business inside a car IMO, but even more appalling is the lack of a plastic tray when using such batteries (stupid Ferrari); even my Hondas have one, and battery is in the engine compartment, where you can easily spot (and remedy) a leak.

Like I said before, all new owners (or those who haven't done it yet) should check your battery compartment immediately, and preferrably replace your wet cell battery with a sealed one for piece of mind.

Finally, I cut the vent tubing about 1-1/2" from fully pulled out, capped it with a trim plug for a factory look, and pushed it in. The reason I said 1-1/2" is because you can't push the tubing in any more, so do that first, put your finger nail at that location, then pull it out, cut, plug, and push in. You can always put it back with a plastic fitting, but it'd be stupid to put another wet cell battery again. New cars come from the factory with exactly the same Optima I installed, which is the 34R folks. No need to change anything; goes right in.

And remember when disconnecting battery to wait 10 seconds after the 'OK' light to fire up engine, then let engine idle for 10 minutes without touching anything. And yes, you'll need your radio code to make it operational again. Oh, and I also took the opportunity to install a battery charger pigtail exactly where I wanted, and directly connected to the battery (pic below). Hope this helps gang.
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Remember I cut the tube, so it's not there. The arrows are pointing to a metal bracket that curves around, and that's where the foot cover screws onto.

The battery vent tube comes from the 'firewall' behind the battery. I didn't picture my plug job, but looks like the many plugs you find in firewalls. When battery is removed, you'll see it right away at the upper left corner. If battery was a bit shorter, you'd see the cap in my picture right by the negative post. Take care.