Xantia 2.0 HDi crank pulley - what does a failed one look like?

[seedy]

The 1999 2.0 HDi (90,000 miles) started making a knocking noise at tickover. Tried the stethoscope and it seemed to inidicate a vibrating alternator. Consulted a few people and got various suggestions ranging from "scrap it" to "replace the crank pulley". The latter sounded more acceptable, so now the Xantia's on stands in the garage and the crank pulley is here on the desk. But how to know if the pulley is shot? No visible signs of wear. No smell of burned rubber. If I stick it in the vice I can get a bit of movement by hand between the inner and outer parts. But is that enough to explain a loud knocking?

[HDI]

Usually a failed one is obvious, like completely separated inner and outer, or if not separated, barely hanging on. The knocking noise could be a failed belt tensioner pulley, the spring loaded one on the top run of the serpentine belt.

[ekjdm14]

Hard to say with any certainty without hearing the sound, I suppose you could try reinstalling the pulley (don't run the engine with it removed!) but leaving the belt off and see if the noise has gone or not. If it's still there, or remains elusive after checking the tensioner as suggested above, perhaps you could take a video of it and might help with diagnosis...

I note you're in Frodsham so not a million miles away from us, so if you're really struggling & you happen to venture towards Congleton in the car I could have a quick look if we're home.

[seedy]

I did run the engine without the belt (with the crank pulley), and it sounded like a 2.0 HDi again. So that suggests to me the sound is coming from one of the things driven by or driving the belt. It rules out anything relating to the timing belt. But all the auxiliaries seem to turn nicely enough, so what I need now is a set of mini belts so I can run with each of the auxilaries in turn to pin-point the culprit. Or I could do what some of the dealers do - replace each item in turn 'till I get lucky.

[RichardW]

Normally they look rusty and often the entire area is covered in rusty dust. When they're getting worse, you can sometimes see a shiny line between the 2 parts. It sounds like the most likely failure TBH....

[Stewart(oily)]

When I bought my current HDI it had a noisy pulley, I must have caught it early as there was nothing to see really, I paint a line of workshop tippex across them to reveal any movement.

[falling-out-with-my-car]

My bottom crank pulley split in the collar at the back if the pulley in my xud9 xantia lump it dislodged the woodruff key And caused a knocking sound it may be that you have a hairline crack in the collar of yours either inside or starting from the outside.

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[lexi]

Having had the pulleys go, then yes that may be the sound of a crank pulley. It can also be the clutch pulley on the alternator. One can sound like the other sometimes. I replaced the crank damper on this one, only to discover it was the clutch bearing on alternator. Crank damper was a £45 Dayco from Mr Auto and the alternator bearing is an Ina bearing, about £32 from Ebay, so quite reasonable to keep your beast on the road.

[Pug_XUD_KeenAmateur]

what I need now is a set of mini belts so I can run with each of the auxilaries...or replace each item in turn 'till I get lucky.

the latter needn't be as outrageously costly as it'd initially sound, as long as you choose a supplier who'll accept returns or find all the bits in a scrappies. Bit of a pain to fit & remove, but sometimes necessary.

Or I understand, but have never investigated it personally, that lawnmower repairs services can be a great source of custom belts: I believe the aux' belt on my XUD was sourced as such (but I got it s'h)

[elma]

A stethoscope is a valuable tool for diagnosing which pulley is noisy. Just loin and listen, it's obvious which ones making the noise. If you don't want burst eardrums start a couple of meters away and slowly move in until the volume is right and do not put the stethoscope against anything on the car, you will never hear again.

[seedy]

It appears to be sorted.Thanks for all of the replies and suggestions. The quandry was, having established that the noise disappeared when the serpentine belt was removed, which of six pulleys represented the problem? The answer came from considering the sizes of the pulleys. Only the crank pulley would explain an engine-speed knock. The other smaller pulleys would turn faster and be out of synch with the engine speed.

Close examination of the crank pulley showed damage to the key slot (see image).

So now we have a new BGA pulley. £58 inl VAT.

I hear the warnings about reliability, but the car only does about 3000 miles per year now, and the original pulley only lasted 90k miles. So...

[ekjdm14]

So was the pulley cracked or was that the only damage? If so, it would suggest to me that the pulley wasn't properly torqued up (perhaps after a cam belt replacement?)

Glad it's sorted now anyway