Hey all,
I haven't found the answer in the forum so here it goes ...

- 4 months ago I changed my belt & crank pulley as they were very worn, though still functional (intermittent noise from worn belt).
- My stilo 1.9jtd has an auto tensioner - new belt went on fine and new crank design came with proper screws so no worries on parts fitting.
- I could hear a slight clacking or tapping a few days later, especially at idle, vanished in 3rd gear. Since then have readjusted the crank pulley to ensure it's perfectly aligned as it should be.
- The noise got progressively worse over 2/3 months and I can no longer ignore it as people in the streets duck for cover when i'm coming. The tapping or clacking noise is really really loud.
- Today I removed the aux belt and ran engine. No tapping. I suspected tensioner pulley as it wobbles a fair bit under operation (probably normal? - circa 15mm) and dismantled it to take a look - a bit worn on the inside from occasional friction but otherwise fine, put it back on with belt, spins pretty good by hand. Noise remained. Sounds like metal on metal to me.

Any ideas ? Tomorrow i'll try sticking a screwdriver and plastic bottle to each pulley with engine running to get a megaphone effect and maybe find it that way. I have other electrical issues which are nuts but I think they really are just bad connectors, earth wire or dirty fuses.

Thanks in advance !

It could be that your alternator pulley bearings are properly shagged.

With the aux belt off, grab the alternator pulley and see whether your can move it from side to side on the spindle, or "in and out". There should be no movement whatsoever.

The pulley fits onto a bearing that is pressed onto the alternator shaft. If the bearings are knackered (your car may have been squeaking for a while and you thought it was a belt) then the bearing cage will eventually collapse and the pulley will move around.

The clanking is probably the pulley hitting the chassis rail (there's not enough room for it to come off the shaft altogether). If you can see marks in the paint where the pulley has rubbed it, then that proves it (although the pulley will be hanging off and even Stevie Wonder would be able to tell it's knackered).

You *can* get new alternator pulleys but you have to remove the alternator to fit them, you will need a suitable press to squeeze them on and before you can fit the new pulley you have to remove the inside sleeve of the old bearing from the alternator shaft without breaking anything. For the money, it's easier to fit an all-brand new alternator... about £105 from Denso.


Ralf S.

Compare your pulley with this new one.

You can see the circular mark in the paint (circled) where the old pulley had crept off the spindle enough to hammer against the chassis.


Ralf S.

Thanks Ralf,
I did actually yank that pulley quite a bit but it seemed very solid. I'll have another go today just to be sure.

Also, having stared at the pulleys in operation, the only two that seem to have any wobble or movement are the tensioner and crank pulley.

Thanks for the picture and advice !
Xav

If the crank pulley is moving then that's the problem.

It has a rubber insert to prevent it vibrating but it should be pretty rigid.

I would check that the bolts aren't fouling. You might be able to look behind the pulley and see the screw threads poking through. If they're catching on the block then that's not so good.. and if they are hitting the block then that might be causing the movement you're seing in the pulley. If you can't see anything then it might be worth removing the pulley anyway and looking for strike marks.

The tensioner hops up and down about 1cm as it goes round.. I think that's normal. A good tensioner will have some resistance in the bearings. If your tensioner wheel whizzes round very easily and makes a racing noise then it might be an idea to change it.


Ralf S.

Right, i've had the belt off again, this time removing the crank pulley off too, seemed fine. But what would I know, the thing runs under way more tension than I can simulate pulling it about. The rubber is seemingly in good nick.

Looking for videos to find the same tapping sound I found a couple that indicated the crank pulley where the sound was very similar. I still had the old crank pulley (inner rubber half shagged) so used it as a test. Bloody hell it as the crank pulley. The part is about 4 months old for petes sake - made by Gates. The old one should hold on a few days till I get it replaced - hopefully under garantee ! Still can't believe the thing makes such a noise when it does physically show any bangs or give in its structure.

Keep you posted.

update.

The old pulley couldn''t stay on in the end, way too shagged. Looked like an old millers grinding wheel wobbling about. Enough to take a video for comparison with the newer Gates one.

I then reinstalled the Gates damper or crankshat pulley, making sure it was nicely lined up before tightening it up. It did make less noise than before at certain revs, but still bloody loud.
Agreed with the shop I bought it at that i'd take it back and they'll inspect it. Figure it's best if they see the noise in action.

I did notice that once the belt back on, looking straight at the pulley trough the wheel arch, the tension seems to force it off centre quite a bit. I wonder if the tension is too hard ? Possible ? Adjustable ? I'm imagine not.

cheers

Interesting....

I really would be surprised if a brand new pulley, made by Gates can be that bad... but anything is possible. Did you buy it yourself, did it come in a Gates box or was it unlabelled, or did someone else tell you it was a Gates pulley they fitted?

And do you have the correct part? Fiat's part number is 55196301 (115bhp JTD) in which case it looks like you should have a Gates TVD1013.

Meanwhile... does your model have power steering and air-conditioning? If so, then your aux belt should be 1270mm long.

The tensioner itself is not adjustable, it just has the same tension no matter what you do with it, so if it fits, then it's certainly the correct part... but if your belt is slightly too short (e.g. 1260mm) then the tensioner will hold it more taut and it would put more strain on the pulley... so also check the belt length.


Ralf S.

Thanks Ralf for all your input on this issue.

Indeed 3 months later and having fitted a new pulley to replace the new pulley I have no issues with tapping or other.

I do have lingering electrical and ventilation problems but i'll start a new thread for them. The dash board is dead and shows no speed and my ventilation seems to never work at all or is intermittent.

Hi all,

Reopening this thread as the same issue is back. Starts off as a light tapping and slowly over 2 weeks increased to a consistent loud tapping sound. Idling the engine when driving along seems to reduce it which could indicate that it's related to tension. Assuming idling tensions the AUX belt while driving.

I installed the pulley and belt myself last time, i'm no genius mechanic but I wa careful to follow all instructions. What could I have done wrong for it to start again? Ideas ?

hope you're all enjoying the summer.

Hi,

If it has a free wheel alternator pulley
Check it has not jammed solid.

If you have not yet replaced the aux tensioner may I suggest now would be a good time to do so.

Good luck.
Jack

Thanks Jack, that's a good idea.

It's worth mentioning that I originally replaced cranshaft pulley and aux belt last year (04/19) since the belt had worn and on inspection I saw the old pulley rubber was worn. Amazingly that old pulley made no tapping noise whereas now a new (they have been modified a bit) does.

Indeed it could be a coincidence and that the tensioner is worn causing the crankS pulley to spin off center too much.

The crank pulley has a hole on the back which is supposed to fit onto a matching pimple on the crank end plate. It's pretty clear when the pimple is not in the hole.. since the pulley rocks about while you're trying to put the bolts in.. so I presume you spotted it.

It's also theoretically possible to fit the pulley on back to front (with the pimple hole facing outwards). Usually you can tell the front from the back, because the inside is cleaner (and has the hole in it) but with a new pulley this difference wouldn't be there.

I *think* a back-to-front pulley would not align straight with the alternator/tensioner etc... and/or it would foul the engine case, in which case it's hopefully very obvious that it's not on right .. but you never know, it might go on apparently okay and line up closely enough that you don't notice, particularly if both faces are new.

If the pulley fitment checks out, then that only leaves the tensioner. I guess it must be "okay" since you need to operate it with a looooong 15mm spanner to remove the aux' belt. If it was seized, you would notice, since you would then be removing the whole tensioner, in order to remove the aux' belt. If you're wondering why Fiat makes you remove the tensioner, to change the aux belt, then it's the tensioner.

With A/C your belt should be 1270mm long, so measure that to make sure, once it's off.



Ralf S.

Hi

It seems the belt tension is to high resulting in bearing failure from tensioners ( static & self tention pulleys )

I recommend verify the:
• aux belt path
• correct belt
• correct pulleys

Thanks all for your ideas.

I took the belt off, it measures about 1280 which is 1cm over. I checked my order from last year when I replaced it. 1270cm was the model (2002 Jtd with a/c).

This seems to imply something g is too tight. When loosening the tensioner pulley I found it to be pretty tight, it’s fairly hard to pivot even with a 15mm spanner and extension of about 30cm as extra leverage.



With motor running I can hear the crankshaft pulley is rattling. It’s a year old. Here’s a vid: https://youtu.be/Vq0e_D2ZNgA

I’m gonna take of the pulley to inspect it. Also I’ll check the alternator pulley is not ceased. Though I’d expect that to lead to a dead battery ....

Cheers

The alternator pulley seems fine, it turns easily by hand. You can feel the weight of the coil but it still spins a little when you spin it

The video shows the pulley flopping about, so that's the cause of the rattle.

But it looks unusual. My pulley (2004 115bhp JTD) has 4 bolt holes in the pulley like in the picture. Four bolts hold it to the crankshaft plate, with the crankshaft end nut poking into the larger central hole. Once you remove the pulley, you can get a socket onto the nut to turn the engine over (for cambelt changes etc.) The 5th hole in the photo is the one that goes onto the pimple, I was describing.


Yours looks like it has a single bolt that squeezes the pulley onto the crankshaft via a metal plate. Is that what it is? From the video it seems that the plate is just not pressing on the pulley enough (which could just be play in the rubber of the pulley) and that's allowing the pulley to move from side to side. It's very obvious if you pause the video and jump forwards and backwards a few seconds at a time.

I also can't find any Stilo (diesel) that has that arrangement... they all seem to have the 4 bolts that would fit into the pulley like in the picture. What model/year is yours?


Ralf S.

Most JTDs seem to have the pulley part number 55196301 which replaced 46447843 (as stamped on the one in the picture).


Ralf S.

Crankshaft pulley seems fine.

As suspected, unfortunately the too tight situation resulted in the crank pulley rubber mould to start collapsing.

Will have to find the reason and replace the crank pulley.