extreme oxidation/elecrolysis at the BATTERY +ve terminal

It sounds to me as though something is causing the battery to leak corrosive vapors at the positive post seal. This could be caused by a failure of the seal itself, or excessive gassing caused by an overcharging situation arising at the alternator/voltage regulator. For a start, with the engine running, use a voltmeter to check the charging voltage at the battery posts. Make sure that the posts are clean and that there are no auxiliary loads such as headlights, cooling fan, etc. Check it at idle, and then have someone rev the engine to around 2500 rpm. The voltmeter should register between 13.5 and 15 volts. More than 15 and you are in an overcharging situation.

 

The battery is leaking, time for a replacement. There is really nothing you can do to repair it long-term.

If it is leaking while on overcharge and gassing, then it also could be allowing oxygen into the battery through the same seal failure while under negative pressure, which will quickly kill it anyway.

 

Correct. Even if it is due to overcharge, the seal has been compromised and the battery is toast.

 

Definitely agree that you need to replace a leaking battery ASAP. A long time ago a friend had a leaking battery on his Datsun 240Z. He replaced the battery and didn't give it another thought, but a few months later his suspension broke. It turned out acid had leaked onto the frame and severely weakened it.

It doesn't sound like your's is actually to the point of leaking acid, but it's definitely a good idea to replace a battery as soon as it shows sign of physical damage. I don't know if they are available where you are, but Interstate batteries are highly regarded in the US.

 

Forgive me for veering a bit off-topic here.

Interstate Batteries are most definitely not available in Malaysia. What many people don't know is that Interstate is not a manufacturer, but rather a marketer and distributor. Virtually all of Interstate's automotive batteries are made by Johnson Controls, Inc., who also manufacture batteries for Wal-Mart, Sears (DieHard), Autozone, etc.

In 2002, Johnson Controls purchased Varta's automotive battery division, thereby becoming a global manufacturer. So, the OP's Varta battery is essentially made by the same company that makes Interstate Batteries in the US.

 

Not really off topic because the OP will probably need to put a new battery in. Good info, I didn't know that about Johnson controls. Even though they make batteries for various brands, they probably make them to different specs for each brand. I put an Interstate in our Maserati, and they offer 3 models for that car. The top-of-the-line one has a kind of translucent white case and I was really impressed with the build quality of casing. The other 2 Interstate models for that car had black casing and look more like typical batteries and maybe aren't as robust. The Interstate replaced an Optima red top that looked cool but didn't last very long.

 

Another solution is the smaller battery from a Mercedes dealer. They have the tabs on the battery bottom that slide into the metal tangs on the battery bracket. Do a search on batteries and you will find lots of posts and the battery does not have to be sealed, a plastic tube connects to a nipple and is routed to below the car. My understanding is battery terminals start to corrode when the battery is worn out and when the sealed battery isn't.
The 348 uses a MT-34R and the "R" means the positive and neg terminals are reversed.
FWIW.


Jeff Pintler
89 348tb, 86tr, 99 360 3-pedal, 05 S-160 Bobcat

 

Over here in the UK then Varta comes with 5 year warranty, in fact most battery manufacturers are standard 4 years now, can you take it back for replacment??