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Posted

Hi all.

My 01 reg Hdi auto makes a chattering noise when at idle and in reverse or drive including sequential. Its always been there while I've owned it and I just put it down to the age of the auto box. But now Im not so sure what's making the noise and our planned drive to and from Spain is looming ever closer.

The noise vanishes as soon as you pull away or select N or P

Any ideas?

Posted
Sound like a heat shields or exhaust bracket or something like that. Or it just could be the fact that theres not enough revs on . When you select drive or reverse if you watch the rev counter youll see that the revs go under the recomended 700rpm untill you acelerate. When in n or p the engine and box are idling at the correct rpm so no rattle
Posted

Sound like a heat shields or exhaust bracket or something like that. Or it just could be the fact that theres not enough revs on . When you select drive or reverse if you watch the rev counter youll see that the revs go under the recomended 700rpm untill you acelerate. When in n or p the engine and box are idling at the correct rpm so no rattle

 

I had a similar thing eventually it became a grating sound, jacked up the suspension and found the underbelly tray was hanging loose and touching the tops of speed bumps, it started as a chattering noise.............just saying Coastline may have a point.

Posted

I had a similar thing eventually it became a grating sound, jacked up the suspension and found the underbelly tray was hanging loose and touching the tops of speed bumps, it started as a chattering noise.............just saying Coastline may have a point.

Wouldn't disagree as I know coastline knows a heck of a lot about c5's and the rev drop idea is sound and on the odd occasion it will do it crawling in traffic.

What I can't find is the thing thats emitting all the noise. I've looked at the exhaust bracket, heat shields, timing cover and engine cover, the under tray has all new fixings and is secure. What am I missing?

Posted
Finding a rattle is a problem in itself. you can normally localise the area and just have a good look round. have you cecked the heat shield on the steering rack also any bolts with washers that are loose will cause a rattle both of these rattles took us over a full day to find. youd probaly be better of taking it to a garage were they can get the car up in the air the bring the noise on and locate it
Posted
Front crankshaft pulley (one with the belt on ) sometimes can chatter ,they are in 2 parts with vulcanised rubber , or alternator one way clutch seized .....they can make the belt flap about alot which makes a chatter sort of noise if you bring revs up a touch it stops , not saying this your fault just thoughts on the symptoms .
Posted

Finding a rattle is a problem in itself. you can normally localise the area and just have a good look round. have you cecked the heat shield on the steering rack also any bolts with washers that are loose will cause a rattle both of these rattles took us over a full day to find. youd probaly be better of taking it to a garage were they can get the car up in the air the bring the noise on and locate it

 

There's a heat shield on the steering rack :o Not spotted that' how do I get to it?

Its not long had a new pully and belts. I also fitted a new top mount and steady but I haven't changed the bottom steady bushes as they looked ok at the time. Could that be a factor? also can the drive shafts chatter???

Posted
Good call costline the heat shield on the rack was vibrating like mad, so I put a stop to that and the metallic part of the chattering has gone. But there's still a noise coming from the off side inner wing. It sounds like the timing belt cover or wheel arch liner vibrating but I just can't find anything moving. Is there a box section on the inner wing I can't get to?
Posted

Check the brake anti rattle spring is still there, I had mine come out and it took weeks to find. Easy fix once I knew what it was.

Done that, no joy.

Posted

check you sh1t tray espacialy where it meets the inner wing guard and the front bumper as both of the points come lose and rattle and bang

Ive got the engine covers, tank cover and under tray off at the mini so we can discount those bits.

But that is exactly the kind of sound and location were talking about. But I can get my hands on all theses parts and not a thing changes. Its like something inside the wing that I can't see or put hand to. Incredibly frustrating!

Weather permitting I'll remove the wheel arch liner tonight and see if that opens up new possibilitys.

  • 2 weeks later...
Posted

Back on the case again, the weather and time got the best of me for a bit. My mobile mechanic friend has my C5 at the moment and reckons the din stops if you add a little extra force to the aux belt tensioner with a bar or similar.

I replaced the pully and fitted a kit not long back. The only questionable part was the two part crank pully the auto factors sold me. The one that came off was a knackerd three part unit with the three luggs sticking out of the front. just for the record the alternater pully is the fixed type.

 

what do you guys think? :blink:

Posted

Update

 

I've changed the crank pulley back to the three part type and almost all the chattering has gone, so much for the auto factors computerised parts catalogue. If I get anymore vibration I'll swap the alternator for the clutch pulley type.

 

would a clutch pulley kit fit on a fixed pulley alternator?

 

I'll run it for a few days and let you know how I get on.

  • 2 weeks later...
Posted

Additional.

Not so much as a squeak from anywhere. In conclusion it must have been the two part pully making the aux belt slap so hard the whole front end of the car shook. I was just blinded by the fact that everything was new and couldn't be faulty.....just never expected some Pratt had sold me the wrong part!

Thanks for all your help guys.

Posted

Has the auxillary belt been set up properly with the eccentric idler ? if the belt is still flapping somewhat it will wear out your new crank pulley faster , no one way clutch type pulleys wont fit in normal alternator shafts .

 

I found that if the aternator is the fixed type pulley the engine normally has the dual mass type crank pulley (to absorb the vibrations that the alt. pulley would deal with ) .

Posted

Has the auxillary belt been set up properly with the eccentric idler ? if the belt is still flapping somewhat it will wear out your new crank pulley faster , no one way clutch type pulleys wont fit in normal alternator shafts .

 

I found that if the aternator is the fixed type pulley the engine normally has the dual mass type crank pulley (to absorb the vibrations that the alt. pulley would deal with ) .

Absolutely right. With the duel mass or 3 part fly wheel its completely smooth. Auto factors don't seem to know that fitting the solid 2 part pully to a car without an alternater clutch will cause the belt to flap. There computers just seem to show both types fit. Would be interesting to see if an alternater with clutch would make the duel mass pully last longer?

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