When I had the engine out of the Micro a year ago I cleaned up and repainted the section of the engine bay under and around the battery. I pulled out the battery to check the level yesterday and there wasn't a speck of paint on anything in the area. Just miles of suface rust, and a couple of pinholes threatening to come through to the outside.
Why is it so ?
Here's my theory: the battery has breather holes in the caps and they breath an acidic mist that gets deposited on the battery top. When it rains hard and some water comes in the air scoops up high on the body, it washes the acidic film off, and deposits it on anything else in the general area.
The solution ? Use a sealed battery. In my case the battery was new a year ago and it seems a shame to toss it, so I've built a sheet rubber tent over the top of the battery, so that water doesn't wash stuff off the top.
What do you reckon ? Crap theory ??
Well I've just rust-killed and repainted the whole area again, so I'll see if it lasts more that twelve months this time.
Nitram
[Edited on 19-12-2004 by Kommer]
It seems reasonable to me. Still, mine's holding out OK with a plain battery. But yeah, sealed might be a good idea.
I think in part your theory has merit. It is more likely that the "acid mist" is deposited mainly on the area under the battery. Over time these acids slowly penetrate the paint and attack the undelying steel. The same thing happens in type 3's where the battery is under the back seat, so I don't think rain landing on the battery and washing the acid off has much to do with it. Therefore the I don't think the tent will help much, if at all.
You are on the right path with the rust-kill and repaint, but you will need to use a very tough paint, like POR15 or POR Hardnose which is highly acid resistant. You may also have to sand blast the area to ensure it is truly clean. Quite often the acid hides in crevices or voids in the steel itself and all the paint in the world doesn't protect from the corrosive materials already under the paint.
Ain't nothin' like the wind in your hair.
You could try sprinkling some baking soda (bicarb soda) onto the battery tray before you put the battery in. this will help neutralise any acid.
alright, lets give it a try... HCl, hydrochloricacid is the active liquid inside a battery. during the charging and recharging process hydrogen is expelled from the solution through the vents in the battery. hydrogen is combustible. if the area is not well ventilated then hydrogen may build up and go boom. (strike out the rubber sheath idea...aka- home made kombi hand grenade).
lets talk forklifts for more insight. battery powered forklifts are cheap to run and versatile, however not to be used in enclosed spaces (boom!). diesel/petrol/gas ones are good for enclosed areas but less versatile...
as for the corroding battery tray, hmmm. this happens with all cars and is due to the battery spills and acid build up/sulfation (?) through the years.
best way to beat it is start using a plastic battery box as the show car guys do when they put the battery in the boot... or use a sealed battry...
hope that helps all, im pretty sure its accurate, just dredging up the old chemistry teachings from 98 here...
everything dies baby, thats a fact..
maybe everything that dies one day comes back..
put your make up on and your hair up pretty..
and meet me tonight in Atlantic city..
With the Mitsubishi cars I've owned the past few years...
the acid Mist from when the battery is charging settles everywhere in the engine bay and all over the top of the battery.. I wash under the bonnet regulary and use car wax..
So, its not Rust -- its actually the acid that eats the holes in the tray etc...
Cover the tray with a rubber mat and make sure its well painted .. POR 15 recommended....
The sealed Battery is the best move...
its probably a good move in a Beetle too...
as the acid mist stays under the rear seat... YIPES...
- Helping keep Air Cooled VWs on the road - location: SCONE in the Upper Hunter Valley - Northern NSW 320 kms NNW of SYDNEY---
you can also get motorbike style batteries where the top is sealed and it has one drain/vent with a plastic pipe you can run below the car to avaid the acid. Mine is Uausa (spelling??)
68Auto said it all though, good clean, good paint and WASH in there regularly!!!
Do the old kingswood country trick and "shampoo the battery" Clean the engine bay while your at it.
Make sure water drains from the the tray and it should stay that way for ages!
Richard, with a clean engine bay and paint still on the battery tray!
