Battery dies randomly

B6/7 S4/RS4
#21

If you end up needing a new alternator, then fyi, B6 platform A4 alternators from the dealer come in two brands: Bosch and some other brand (I forget at the moment).

The parts counter guy at my local Audi once told me that for my 2004 A4, I should check my old alternator in my car, and buy a replacement for whichever one of the two brands is currently under the hood of my car. He had concern about fitment between the two brands, but he admitted that he wasn’t 100% sure if there was and difference

#22

*if there was any difference

#23

It’s worth considering that even if you get 13+ volts with your engine running (alternator), and if you get 12+ volts with your engine off (battery), then your battery still in fact may be toast, if it has been drained flat more than once, or if it has been left un-used/parked long enough for the battery to freeze solid dead. These situations can severely damage the capacity of a lead acid battery (normal car battery), so even if it “charges”, and even if it shows 12V or more with the engine off, then it still may only have the capacity of, say, a few AA batteries. In other words, there may be enough capacity left to both store a charge and show a charge, but there may not be enough punch/capacity on demand to turn an engine.

#24

If you’ve got a list of things to do with that car, then consider putting a new driver’s side bum cushion on your list. The cushion can be bought separate from the leather. NOT used. New. With that many miles, you seriously won’t believe how new the car will suddenly feel when you sit in it, after installing a new bum cushion. I did this once on a car I had, when it hit 200,000km (about 125,000 miles). To say it was “an amazing difference” is under-selling it. HUGE upgrade in my opinion.