How to neutralising car-battery acid splashed into car engine compartment.

[Ricky C]

I just bought a 1997 Nissan Primera. It has apparently had a boiling battery at one time, causing the battery acid to spray out. Much the of the crank case and gearbox has surface corrosion as a reult (showing up as whitish powdery deposits all over). I don't think this is a serious problem since it comes off when rubbed with wire wool.

More of a concern is the steel parts that have rusted as a consequence. FOr example the acid leaked aver the automatic gearbox's steel mounting brackets which are just behind the battery compartment and consequently showing some rust. I'm not sure how much I should be worried about this. The mountings appear to be made of pressed 1/8" steel.

I was thinking of spraying everything under the bonnet with a soda solution to neutralise any lingering acid that could cause further corrosion, but someone has suggested to me that soda (or bicarbonate of soda) will also corode the aluminium engine!

If that's correct. can anyone suggest anopther line of remedial action to neutralise any remaining acid lingering in the engine compartment?

Many thanks

RickyC

[Ian Stirling]

IMO, it's unlikely that anything is lingering. But, I'd spray it with a fairly dilute solution of bicarbonate of soda, say 100g of solid in 5l of hot spray with washing-up liquid. Leave a couple of hours Then take the hosepipe (on fine spray) and spray for a couple of minutes.

Bicarbonate of soda will not appreciably degrade aluminium in the short term. Soda (lye) is a much, much more aggressive chemical,and may.

The right way of course is to disconnect all the rusted parts, wire brush them, and repaint. But this may not be practical.

[mrcheerful]

just pressure wash the whole lot, then if it worries you remove each rusty bit, strip and clean it and repaint.

[Andrew Chesters]

Flush it with water. Grease exposed bits afterwards, perhaps?

[The Natural Philosopher]

Use a very mild alkali like diluted bleach to get vestigial acid off, then flush with lots of water, then look at treating the rust.

The phosphoric acid stuff like jenolite us not bad, if painted afterwards

[P.R.Brady]

I'd say bleach is pretty corrosive! Phil

[The Natural Philosopher]

Not the hypochlorite stuff. Not dliuted and on steel.

Its not as bad as e.g.plain salt is when bimetallic contacts are in existence.

[Ricky C]

Thanks to you and Ian. Re: pressure washing: I have one of those DIY patio cleaner pressure washers, I could use but am concerned about water getting into electrical components such as the alternator, wiring, etc. Should I be?

Thanks..

RickyC

[The Natural Philosopher]

Get the engine hot, then spray it but not too hard.

The underbonnet areas of cars are expected to get a lot of water up from the road - things are pretty protected. The hot engine will dry off fast.

[Ian Stirling]

I'd personally worry about using an actual pressure washer. The pressures generated are quite high enough to force water through seals. I'd rather use a hose on spray. You want lots of water everywhere, not really at extremely high pressures.

[Dave Liquorice]

But not at 100 bar and I think you'd be surprised how dry most engine compartments remain even in the most abismal conditions. If it was me I'd used a solution of bicarbonate of soda left for an hour or so and a good gentle wash down with lots of free flowing water.