Accessory Be;t: Alternator & Power Steering

[Amphitryon]

Today I was driving the car when there was a slight burning smell and then the power steering stopped working and the alternator warning light came on. I obviously expect that this is due to a common belt having broken, what used to be called the fan belt except it looks like this model has an electric fan. As soon as I got the car parked, which was not at all easy as without the power steering it is very hard to manoeuvre, I had a quick look under the bonnet and no such belt is visible. I suspect it may be under some plastic cover - does anyone know for sure? How easy is it to get to?

A couple of related questions: with the battery not charging from the alternator I wonder if it will need an extra charge. Are there any hazards to be aware of in disconnecting the battery to charge it?

The air suspension, newly fixed with a compressor service kit from bagpipingandy, and which has been behaving very well, went down to level one and refused to raise as if forbidden by software. What I mean by that is it does not accept the instruction to raise, so the "up" light is on and the next level light is flashing etc. but the up light comes on only very briefly and immediately goes out again without any warning light. Any idea what is happening here?

P.S. I tried searching to see if this has been answered previously but didn't find anything.#

P.P.S. I forgot to say this is on a 2.5 TDI allroad.

[Amphitryon]

It seems the "similar threads" feature is better than the search engine. Anyway from one of those threads, some more searching and looking at the car I have learned a little more.

This car has two fans, one looks like a normal viscous fan, presumably driven by the failed belt, the other electric.

There is a service mode where, after taking off the front bumper, the front of the car can be moved forward a little bit without having to remove the radiator etc.

What I don't know is whether this service mode would be sufficient to gain access to the belt. Watching a video of putting the car in service mode this belt was clearly visible but on mine, looking down with a torch, I can see neither a belt or empty pulleys where a belt should be. Where I saw a plastic cover the day before yesterday is where I would expect the timing belt to run, i.e. at the ends of the cylinder heads but there still seems to be a plastic cover lower down. I can't see if this is a separate cover or the same one.

Then there is the question of why the belt should have broken in the first place. Other than just getting old and perished I have read that the head can snap off the bolt holding the tensioner and the tensioner can wear so it no longer provides enough tension.

From what I remember the belt failed when pulling away from a junction and turning at the same time, i.e. using the power steering. There is a slighly clonk from the front suspension. Does the power steering have a pressure limiter and therefore limit the load the power steering pump can put on the belt or can the pump put up so much resistance it would break a belt that was otherwise in good condition?

[Hannu5]

Did you get sorted? You're right that the "ancillary" belt is covered which you'll have to remove to change the belt.

Again as you perceive it, front of car moved to service mode makes access easy.

It's just about time consuming but not really difficult, may need to remove headlight units first to see and work on the detachment of front.

If belt was old/impaired that may have caused failure. But check and be prepared to change idler pully/ bearing if noisy of show any misalignment when you get in there.

The main cam belt is further inside this ancillary belt and not needed to work on it to change ancillary.

Tension is, maintained by a sprung pully that you don't have to adjust, it's all fairly simple to complete.

[Hannu5]

To add, without the alternator running I doubt if the suspension will function and will probably abort requests.

Also don't drop the windows else they too may not come back up, unless you run jump leads from another car to it.

Battery disconnect doesn't seem to affect mine (non allroad 2.5 Quattro estate) but you don't have to just to work on belt. If you change alternator, for example, it's wise as you've got main positive link from terminal to remove on alternator rear.