W210 alternator pulley warning!

[coneybiller]

Afternoon all. I have an E320cdi 2002. I've had a squeak from the belt area for around a month. I've ignored it as it only happens at idle, once warm it disappeared all together.
The other evening I arrived at work and it sounded like I had an enraged budgey under the bonnet! Looked into it and it was coming from the alternator area. So I thought to myself I must get that sorted. The next day I had forgotten about it, got to work and there was the worst rumbling noise ever! It actually sounded like I had a cam lobe that was flat and the noise was coming from all over the place!
Took it steady and just got onto the M4 and the alternator light came on and the steering went heavy. Pulled straight over and could see the belt was stationary. The alternator pulley had completely sheared off the spindle. Recovered from Reading to Cheltenham with the most self centred, chatty, recovery man I've ever met (doh).

Luckily for me it had done no more damage. Not so lucky is the fact I thought it was going to take 5 mins to replace the pulley... even with the special tool, we could not get the remains of the pulley off of the spindle. Even removed the alternator to try and remove it. I had then found that the bearings were all exposed and dried out on the alternator itself. As I needed the car ASAP the only way forward was to get a new alternator... £425 later and 6hrs of graft(including waiting for parts to arrive and lunch) she's fixed! That was trade price too, GSF car parts wanted £848 retail!

Needless to say, If you hear a squeak or a squeal from the belt area, get it fixed ASAP!

 

[a111r]

Just got a new pulley for mine.
The key indicator here being a cyclic, rough idle and a 'bouncing' belt tensioner.

 

[renault12ts]

Been there, done that...

 

[grober]

A lot of folks don't realise many of these alternator pulleys on modern cars are of the overrun type. The function of the overrunning alternator pulley is to decouple the generator from the rotational irregularity of the crankshaft of an internal combustion engine or puting it another way- you want the engine driving the alternator not the other way round. So rather than a simple drive pulley these are more complex assemblies which can and do go wrong. If caught in time its a relatively inexpensive pulley swap as the OP said.

 

[coneybiller]

Indeed, an expensive "I must get round to that soon - oh no, too late!". I had no belt wobble or any other issues other than a squeak that got louder over time. Never broken down on the motorway before, it wasn't fun. Quite unnerving when large articulated lorries thunder past inches away, while your having a nosey under the bonnet! I'm just glad it wasn't cold/raining/windy or it would of been even worse standing behind the barrier!

 

[Auto-mobile]

The easy test is if your power steering isn't electric, put the steering on a full lock and you will hear the belt flapping around and squeaking, also look at the belt that passes the alternator pulley and you will notice it is flapping around.