A couple of weeks ago the zafira spat out its crank pulley. Rang around for a few prices and nearly cried, even the trade price is just under £100 
Off to the bay to find a bargain, result! £33 delivered, that'll do nicely. What could possibly go wrong...
Part arrives a few days later and it's almost identical to the one that came off (I know there isn't much you can change in a pulley design!)
Test drive shows a loud slap/knock between 1200-1500 revs, upon inspection the bottom run of the belt from the ac pump to the crank is flapping around badly, could be the belt was stretched?
New belt, still slapping/knocking like hell on the over run. New tensioner too then!
New tensioner on. Belt has now calmed down, but now it has an annoying thud/knock when turning the wheel slighly as the revs drop through the 1200-1500 range. Only when the engine is idling though, if it's under load, even if it's only trundling along at 1300 revs there's no noise.
Looks like there is a reason that the £33 tensioner cost £33
Coughed up the £100 for the proper part
Proper pulley fitted, noise still there!
New pulley, new belt, new tensioner, noise still there. Argh!
What did the noise turn out to be, after I'd replaced the consumable parts of the system involved?
Obviously it was a sticky calliper slider on the front drivers side wheel. Obviously. (yes, it took ****ing hours to find that one!)
Leaving the radio turned on (turned on but not up) was enough to flatten the battery so I've just splashed £80 on a new Bosch S5 to drain the last few quid out of my "toys" fund. Nice of the battery to last all winter and give up in the last few weeks of the cold.
...and breathe...

Off to the bay to find a bargain, result! £33 delivered, that'll do nicely. What could possibly go wrong...
Part arrives a few days later and it's almost identical to the one that came off (I know there isn't much you can change in a pulley design!)
Test drive shows a loud slap/knock between 1200-1500 revs, upon inspection the bottom run of the belt from the ac pump to the crank is flapping around badly, could be the belt was stretched?
New belt, still slapping/knocking like hell on the over run. New tensioner too then!
New tensioner on. Belt has now calmed down, but now it has an annoying thud/knock when turning the wheel slighly as the revs drop through the 1200-1500 range. Only when the engine is idling though, if it's under load, even if it's only trundling along at 1300 revs there's no noise.
Looks like there is a reason that the £33 tensioner cost £33

Coughed up the £100 for the proper part

Proper pulley fitted, noise still there!

New pulley, new belt, new tensioner, noise still there. Argh!
What did the noise turn out to be, after I'd replaced the consumable parts of the system involved?
Obviously it was a sticky calliper slider on the front drivers side wheel. Obviously. (yes, it took ****ing hours to find that one!)
Leaving the radio turned on (turned on but not up) was enough to flatten the battery so I've just splashed £80 on a new Bosch S5 to drain the last few quid out of my "toys" fund. Nice of the battery to last all winter and give up in the last few weeks of the cold.

...and breathe...