Gremlins

[Ameiseuk]

Could the oil leak have caused some damage to the alternator?

I've seen electrical gremlins manifest themselves through a voltage spike coming from a faulty alternator - a generic OBD reader with the ability to track voltage should be able to map what the alternator is doing.
Plug it in and take the car for a good drive and review the results.

A good clean up of heavy pos and neg terminals would also be a cheap fix if it cures the problem.

[Audidothat]

Leaking battery - I took the battery out and everything underneath is covered in a light film of battery juice, lots of yellowing and corrosion. The corner of the boot closest to the battery was dampish. The outside of the battery was wet.

Please see photos. Any ideas what those modules are? I have disconnected and checked, visually they look ok.

Do we think I have found the culprit?

I hope this is going to be ok.

[snapdragon]

Wow, never seen that before. I would put sodium bicarbonate all over it to neutralise it. Does the battery have that 5mm hole in the end that that pipe plugs into like the original? Did it come out?
Do you think it boiled up or is it cracked?

[MikkiJayne]

If it has boiled that is indicative of a dodgy alternator regulator. Have you checked the voltage when its running? It should be 14.4 max at the alternator output. Usually that's about 13.8-14.0 by the time it gets to the battery.

I'd expect the battery monitor on the D3 would log a fault for this though so it may simply be physical damage.

[Audidothat]

Originally Posted by MikkiJayne

If it has boiled that is indicative of a dodgy alternator regulator. Have you checked the voltage when its running? It should be 14.4 max at the alternator output. Usually that's about 13.8-14.0 by the time it gets to the battery.

I'd expect the battery monitor on the D3 would log a fault for this though so it may simply be physical damage.

I just googled the symptoms of a poor alternator regulator and I think that's me! Dimming flickering internal lights, inoperative dash gauges/readings, etc etc

I bet the front of the car has to come off to replace!

[MikkiJayne]

Most of the control module (ecu etc) will report battery voltage. However, if the lights are flickering its likely there are fluctuations in voltage which the modules won't show. You'd need an oscilloscope to see that.

I think its all generally pointing to the alternator though. I would expect at the very least you'll need the front end in service position to release the drive belt.

[Audidothat]

Just had a quote of £880 from Audi to change the alternator regulator. Damn it.

[Audidothat]

Yes to the hole and the black pipe was connected. It doesn’t looked like it has split or cracked anywhere so perhaps as you say, it boiled up!

What I can’t figure out is whether a crazy battery would cause all the electrical glitching? Anyway, at the very least I have to get a new battery so here’s hoping!!

[Audidothat]

Sorry MJ we were typing at the same time! I can’t check the voltage so wouldn’t know. I imagine that would be resolved via a new alternator?