What's that noise?

MikeT · Post by **MikeT** » 07 Feb 2008, 20:12

I heard it when queuing in traffic, with a wall to my right so the noise was deflected back toward me. It was rare and intermittent and hard to reproduce but sometimes a blip on the throttle would induce it as the revs dropped to idle.

It sounds to me like the occasional clacking noise heard when bearings beginning to fail, or a loose chain for instance. That sort of muffled, solid, metal, clacking sound of excess freeplay allowing unwanted collision. It seems to coincide with engine decceleration, just before it maintains steady idle.

Considering the recent cambelt & waterpump replacement (appx 1000 miles ago) could it be something in this area? It does seem to eminate from behind the front wheel. Maybe I should have bought new tensioners at the same time? In retrospect, I should have had the auxillary belt changed too.

Also, as I shut off the engine, there's sometimes a single "clack", as it all comes to a sudden rest. It actually sound like something snapping but I'm not too worried

XantiaMan · Post by **XantiaMan** » 07 Feb 2008, 20:46

Mine does exactly the same as yours, also had a water pump and cambelt and aux belt, was quiet before. Its the auto tensioner that is worn on the aux belt, something else for the list but apart from an annoying noise, seems ok. I just keep the window shut!

citronut · Post by **citronut** » 07 Feb 2008, 23:16

dont be to at ease with aux/drive belt/tensioner noise or isues, because its been known for the aux drive belt to go and then wind its way round the crack pully and under the cam belt

regards malcolm

steelcityuk · Post by **steelcityuk** » 08 Feb 2008, 11:14

If your car has a rubber damped crankpully it could be that that's starting to go. If so you could paint some lines right across it and see if these start to 'split'.

Sorry if I'm telling you what you already know!

Steve.

MikeT · Post by **MikeT** » 08 Feb 2008, 13:07

We had to change the crank pulley and the rubber damper (see thread Mike's Cambelt) due to some unexplainable damage we discovered. Taken from a breakers, it's possible the damper may be failing though would that create the sort of noise I described?

I notice Haynes state that Citroen specifies the use of a special tool to correctly set the auxillary drivebelt tension. It goes on to state that an approxiamate setting can be achieved without it but insists the tension should be checked with this tool as soon as possible. Then it confuses the issue referring to cars with automatic adjusters and those with manual adjusters. It then explains the reasoning - too slack and it will slip and maybe squeal whereas too tight and it will wear the alternator bearings.

Perhaps that's what I'm hearing.

jgra1 · Post by **jgra1** » 08 Feb 2008, 14:42

Mike very doubtful for you, but on mine one of the AC pump bolts (lower) has lost its nut.. scraping noise against AC pulley.. impossible to get to back of it without removing Aux belt, alternor at least.. soo annoying

good luck,
John

reblack68 · Post by **reblack68** » 08 Feb 2008, 18:36

MikeT wrote:I notice Haynes state that Citroen specifies the use of a special tool to correctly set the auxillary drivebelt tension. It goes on to state that an approxiamate setting can be achieved without it but insists the tension should be checked with this tool as soon as possible. Then it confuses the issue referring to cars with automatic adjusters and those with manual adjusters. It then explains the reasoning - too slack and it will slip and maybe squeal whereas too tight and it will wear the alternator bearings.

Haynes have the modern disease of covering themselves so much that it's hard to tell what's necessary and what isn't. They said something similar about the timing belt on my Renault engines but further research suggested that it's not even possible to use the tension checking tool with the engine in situ. I'd guess it's a similar story with their advice on your drivebelt.

MikeT · Post by **MikeT** » 22 Feb 2008, 20:20

I have an update on this now, thanks to Citrojim pinpointing it for me.

It's a bit of a shocker

but if you have already read & understood Citrojim's thread "Mikes Cambelt", you'll probably not be surprised.

The problem; the crankshaft pulley bolt was probably not at the specified torque.

Now, I was responsible for torquing that bolt and I'm pretty sure it was correct at time of fitting but in hindsight, I think I should have at least bought & fitted a new bolt and possibly used loctite as well. So I shall be rectifying that very, very soon!

lolingram · Post by **lolingram** » 23 Feb 2008, 14:56

DO NOT tarry in changing the bolt... a new one will have the Locktite coating. The noise is the key chewing its way into the slot in both crank and pulley... believe me as I have suffered. Do check the pulley and key for damage and replace if in any doubt at all.

The problem; the crankshaft pulley bolt was probably not at the specified torque. Rolling Eyes

Now, I was responsible for torquing that bolt and I'm pretty sure it was correct at time of fitting but in hindsight, I think I should have at least bought & fitted a new bolt and possibly used loctite as well. So I shall be rectifying that very, very soon!

MikeT · Post by **MikeT** » 23 Feb 2008, 17:31

Thanks for warning lolingram, I had to order the bolt so hope to get it next week. Did you see the state of the pulley as we found it?

http://www.frenchcarforum.co.uk/forum/v ... hp?t=22930

Post by **CitroJim** » 23 Feb 2008, 18:16

Thing is Lol, Mike's problems are compounded by having a badly worn crank-tail keyway as a result of the damage caused to the cambelt sprocket and pulley. The keyway, if I recall correctly, has worn keystone shaped and would really need a specially cut key to do a proper job.

What is happening is because the keyway is worn, the crank pulley is able to "give" a little on its rotational axis and this is acting like an impact wrench on the crank bolt and over time it loosens.

Mike and I now know precisely why the crank bolt was originally found to be on so tightly it was very near impossible to undo

Strictly, Mike needs a new crank

For now, either do the crank bolt up very tightly again with Loctite or do something despicable with Chemical Metal or a welder!!!

Lol, did you not have a very similar problem a long while ago? I recall you did something rather skillfully to overcome it.

lolingram · Post by **lolingram** » 24 Feb 2008, 06:08

Hi Jim.

Yes, I had exactly the same problem, and made up an (now) offset key to correct timing, from some gaugeplate, to more or less fit into the rather horrid messy hole in the crank tail. Together with a replacement cam drive pulley and a NEW vibration damper/aux drive pulley (never worth using s/h here IMHO), bolted it all together with lashings of Locktite 638 and a new bolt. Hasn't moved since - 100% success.

See: http://www.topcorp1.com/swing/coffincli ... uote]Thing is Lol, Mike's problems are compounded by having a badly worn crank-tail keyway as a result of the damage caused to the cambelt sprocket and pulley. The keyway, if I recall correctly, has worn keystone shaped and would really need a specially cut key to do a proper job.

What is happening is because the keyway is worn, the crank pulley is able to "give" a little on its rotational axis and this is acting like an impact wrench on the crank bolt and over time it loosens.

Mike and I now know precisely why the crank bolt was originally found to be on so tightly it was very near impossible to undo Evil or Very Mad

Strictly, Mike needs a new crank Twisted Evil For now, either do the crank bolt up very tightly again with Loctite or do something despicable with Chemical Metal or a welder!!!

Lol, did you not have a very similar problem a long while ago? I recall you did something rather skillfully to overcome it.[/quote]

Post by **CitroJim** » 24 Feb 2008, 18:32

Thanks Lol, making that key must have been rather time consuming. Good effort

Yours was remarkably bad

Mike's is nowhere near as bad thankfully.

I can only begin to guess at the harsh treatment that resulted in that damage. Have you any idea how it happened?

MikeT · Post by **MikeT** » 24 Feb 2008, 21:07

citrojim wrote: Mike's is nowhere near as bad thankfully.

At least, when we saw it last it was, Jim.

lolingram · Post by **lolingram** » 24 Feb 2008, 22:13

Oh yes!

Lady know-it-all last owner changed the cambelt herself (and the clutch!). All f***d up and had to be re-done. Clearly the bolt had not been replaced nor tightened correctly. Also aux belt train had to be re-done as it was thrashing around. Car has only 72k on the clock, and in the end was not TOO dear to fix, but what an effing hassle.

She was actually proud of herself, but I put her right on that score using pretty straightforward Lancashire English (I am not from there, but she is from Bacup)!

Thanks Lol, making that key must have been rather time consuming. Good effort.

Yours was remarkably bad. Shocked Mike's is nowhere near as bad thankfully.

I can only begin to guess at the harsh treatment that resulted in that damage. Have you any idea how it happened?