aux belt flapping

[mjb]

The missus' car is a bit unwell... Makes a right racket and the other week I eventually got round to putting new top engine mounts on. The old ones were torn to shreds, and I know the bottom one's in a sorry state - someone else is going to suffer changing that in a week's time...

So it went in for an MOT. Failed on the exhaust flexi-joint and the cat - no doubt a result of the engine bouncing around. So it's got new bits fitted and now it's got some right nasty vibrations under torque to the point the wife calls me cos she doesn't want to drive it. No problem I think - the bottom engine mount's still shot and the new bits are making it obvious. However, the (trustworthy) mechanic who does the stuff I can't be arsed (or back's too knackered) to do thinks it's due to the aux belt slapping around. He tells me to get on the ground and have a look

Lo and behold, the aux belt is slapping around everywhere between the aircon and crankshaft pulleys!!! I'm still positive the vibration on torque is due to the mount, but I can hear that the hideously loud diesel slappy noise the car has is actually the aux belt, and it's not good.

Had a closer look this afternoon, but I hate to say I can't say for sure what it is. The tensioner is bouncing around like mad, but I think that's a symptom rather than the cause as the pulley's fine and it springs back with vigour. The alternator pulley seems a little wobbly when hand-spun, but is perfectly still when the belt's on. The crankshaft pulley does seem a little wobbly when driven though, but not very. Everything else seems fine

I'm going to replace (or get it done by my mechanic when he does the bottom mount - HA! No wheelarch liner faffing for me!) the crankshaft pulley, as it's due replacement anyhow, and the year-old belt because it looks 10 years old due to this abuse, but does anyone have any other thoughts on this?

[grasmere59]

Check the pulley on the alternator if it is the clutch type and it's failed the aux belt will flap all over the place.

[crackpotterpig]

if the aux belt tensioner is moving around loads and not keeping the belt tensioned it should be replaced,be careful as in certain circumstances if the aux belt snaps or comes off the pulley it can get wrapped around the crankshaft pulley and displace the timing belt with potential further damage.

[mjb]

Check the pulley on the alternator if it is the clutch type and it's failed the aux belt will flap all over the place.

I don't think it's clutched - if it is, it's internal because the pulley's small and simple (unlike the clutched aircon pulley) and rotates *something* inside the casing. Also, there's an idler and the aircon pulley after the alternator before the belt gets to the flapping section, so I don't understand how that could cause it

[grasmere59]

Have a look at this topic viewtopic.php?f=27&t=13143&start=60

[stevewalsh]

Sounds like crankshaft pulley on way out

[mjb]

Have a look at this topic viewtopic.php?f=27&t=13143&start=60

Oh yeah, that's it to a tee. Cracking 1980s video! Already got the pulley on its way, but looking at that thread I guess I should be prepared for an alternator swap too :/

[Welly]

I think it was found by Cap'n Jack that the LAST thing he changed (the alternator) cured the problem

[steve_earwig]

Didn't he say that it hasn't cured it 100%?

[Welly]

Not sure but it makes perfect sense that the rotating pulley would have 'sticky spots' and keep grabbing at the belt making it flap around. This would make it quite an urgent repair in my book as you don't want the belt to jump off.

[mjb]

Not sure but it makes perfect sense that the rotating pulley would have 'sticky spots' and keep grabbing at the belt making it flap around.

The trouble is there's six rotating pulleys to choose from... As I said, I'll do the crankshaft first, because the car's old enough to want a new one anyway

This would make it quite an urgent repair in my book as you don't want the belt to jump off.

Which is why I've got the car in my garage until it's sorted, although it has been a problem for as long as we've owned it. I can't let it be driven any more though now I know just how bad it is. SWMBO is currently driving the father-in-law's 307 hdi...

DIESEL ADDITIVE MINIMUM LEVEL
and now
UNBLOCK FUEL FILTER

urgh. Bloody FAP. Bloody french messages ("fuel filter" actually means the FAP's clogged, not the fuel filter)... bloody pp2000 laptop not running without mains power any more meaning a forced regeneration (after refilling the eolys of course...) has to be done next to the house... Best tell the neighbours to close their windows for that one!

Having a bad time with Pugs at the moment.

[Captain Jack]

Didn't he say that it hasn't cured it 100%?

The aux belt is 100% now. It's the steering wheel vibration that's still not at 100% but it's not audible so I am leaving it for now!

[Doggy]

Not sure but it makes perfect sense that the rotating pulley would have 'sticky spots' and keep grabbing at the belt making it flap around.

The trouble is there's six rotating pulleys to choose from... As I said, I'll do the crankshaft first, because the car's old enough to want a new one anyway

This would make it quite an urgent repair in my book as you don't want the belt to jump off.

Which is why I've got the car in my garage until it's sorted, although it has been a problem for as long as we've owned it. I can't let it be driven any more though now I know just how bad it is. SWMBO is currently driving the father-in-law's 307 hdi...

DIESEL ADDITIVE MINIMUM LEVEL
and now
UNBLOCK FUEL FILTER

urgh. Bloody FAP. Bloody french messages ("fuel filter" actually means the FAP's clogged, not the fuel filter)... bloody pp2000 laptop not running without mains power any more meaning a forced regeneration (after refilling the eolys of course...) has to be done next to the house... Best tell the neighbours to close their windows for that one!

Having a bad time with Pugs at the moment.

De-FAP it.
You know it makes sense.

[rwb]

I thought it was a HDi 90?

[Captain Jack]

I thought it was a HDi 90?

His 406 is. The 307 HDI probably has that FAP filter on all diseasel engines.