C5 Cam Belt

[Guest PeterHartley]

C5 HDi 2.0 (2004)

my cam belt was changed at the 87.5k service but had only done 5000 miles by last Monday when the belt snapped. No cause identified for this, so reassembled with new belt. Ninety miles later it has snapped again!.

A week or so before this there had been a noise which I thought sounded like a slipping clutch (engine revs increasing disproportionate to road speed/acceleration), but the clutch is apparently OK & did not need attention. The noise was heard again during my 90 miles of carefree driving; could this be relevant?

(confused!)

[Johndouglas]

What damage was caused when the belt broke the first time - that is at 5000 miles after replacement?

[Ronin]

I'm not too sure about the C5 belts as I havn't done one yet but I've had lots of experience with changing other car makes. I can only offer a generalised approach to your problem.

 

Premature cambelt failure can happen for a few reasons.

1. The tension on the belt has been too tight or too loose. Often associated with a whining noise when tight or a rattle when loose.

 

2. faulty pre-tensioner or guide rollers. This causes all the symptoms of the above and leads to imminent failure. Alfa Romeo for example reccommend the guide roller and pre-tensioner to be changed during every cam belt replacement.

 

3. Faulty bottom pulley or waterpump pully. Pulleys can become loose with wear and can start to vibrate, causing cambelt failure. Water pump bearings often sieze or slow down with corrosion and wear. This can put extra tension on the cam belt and os associated with a high pitch squeel.

 

4. Damaged teeth on upper cam pulley. A lot of "DIY mechanics" try to fit cambelts with "home made" locking systems. i.e. screwdrivers! or they dont have the right tool for the rollers etc.

They find it difficult to place the belt on in the correct position or tension so resort to "tapping with increasing force and language" the belt onto the teeth of the cam pulley with a hammer. Naturally this results chips and dents on the metal which wears through the belt like a strimmer on overload!

5. This one is very rare nowadays but it could be a faulty belt from new. Try a different manufacturer. Never scimp on cambelts. You get what you pay for and it will show in the miles you do.

 

6. OIL on the belt! check for leaks from oil seals at the top and bottom that can get onto the belt and lead it to slip. Oil seals can fail due to increased back pressure from clogged pipes and/ or over filling the engine oil. Check the dipstick to see if it pops out of the holder when driving. This is a sure sign of excessive back pressure.

 

Most of these faults will cause eventual failure. The only way to make sure is to replace the guides/ rollers and any pump that has been on the car for a long while. prevention is far better than the cure. Most problem can be intermittent with heat and milaege so when the engine is cold a bit of play in these items can go unnoticed even to a trained eye.

 

As far as the clutch goes, I've never heard of a clutch slip that causes belt failure unless it was excessive revs for over a short period(40 seconds + at max revs continously). If the cambelt area has oil leaks, the chances are that the other crankshaft oil seal at the gearbox end is leaking too. This results in oil on the clutch plate thus causing slip.

 

Don't worry, these are suggestions of ALL that can go wrong and by no way means that all of these symptoms are the cause. It is more than likely that you may have one issue in this macabre list that is causing the premature failure.

 

I hope you get it sorted m8 and I hope some of the advice i've given has helped.

Please let us know how you get on m8.

[Guest PeterHartley]

What damage was caused when the belt broke the first time - that is at 5000 miles after replacement?

 

Apart from the belt itself the needle roller bearings on the rocker assembly took all the force. No damage to valve stems etc. The cam belt was in shreds but there was no sign of leaks from the water pump or oil seals and no play on any of the items driven by the belt. The belt was a genuine Citroen part too! So the repair was limited to another new belt and a set of rollers.

I heard the noise [of the belt parting] followed by an 'anti-pollution fault' warning on the display screen; exactly the same when it happened again last night. I wonder now whether the noise that I had attributed to a slipping clutch may be related but I'm stumped over why if the belt was slipping the engine didn't cut out immediately? (clearly I'm no mechanic)

[Ronin]

Apart from the belt itself the needle roller bearings on the rocker assembly took all the force. No damage to valve stems etc. The cam belt was in shreds but there was no sign of leaks from the water pump or oil seals and no play on any of the items driven by the belt. The belt was a genuine Citroen part too! So the repair was limited to another new belt and a set of rollers.

I heard the noise [of the belt parting] followed by an 'anti-pollution fault' warning on the display screen; exactly the same when it happened again last night. I wonder now whether the noise that I had attributed to a slipping clutch may be related but I'm stumped over why if the belt was slipping the engine didn't cut out immediately? (clearly I'm no mechanic)

 

Just a quick few questions Peter.

When you say "the belt was in shreds" was it damage to the belt along the length of the belt or was it across the belt?

 

Also were any teeth or grooves on the belt missing or did the they all look worn? For example instead of a castle battlement look, did they look rounded on one edge?

 

Was the back of the belt shiny or did it still have the white print on it?

[Guest PeterHartley]

Just a quick few questions Peter.

When you say "the belt was in shreds" was it damage to the belt along the length of the belt or was it across the belt?

 

Also were any teeth or grooves on the belt missing or did the they all look worn? For example instead of a castle battlement look, did they look rounded on one edge?

 

Was the back of the belt shiny or did it still have the white print on it?

 

 

There was a thin remnant of the belt, I think it was still a complete circle but the remainder was in thousands of fibrous fragments that had to be blown out with an air line. I didn't pay much attention to the back of the belt but today (Tuesday) the second repair will start so I'll ask more about the condition and also check on the state of the latest debris

[Ronin]

There was a thin remnant of the belt, I think it was still a complete circle but the remainder was in thousands of fibrous fragments that had to be blown out with an air line. I didn't pay much attention to the back of the belt but today (Tuesday) the second repair will start so I'll ask more about the condition and also check on the state of the latest debris

 

Ok m8, no problem. You can tell a lot from a snapped cam belt in the way it is damaged. It can throw up some areas to start looking for the re-occuring problem. If this second belt has gone in a similar manner then we can presume a mechanical link in the belt's route is to blame.

I think the clutch slip has a related issue to why the cambelt is going so quickly. It could have some bearing on it if the engine was over revving continiously but if not, it sounds as if it's a symptom rather than a cause.

There is very good reasons why I'm asking these questions. so bear with me and get as much info from the technicians as you can.

 

Let us know what you can see when the belt is removed m8 ok and we can take it from there.

 

If I was a betting man I would put a couple of quid on it being one of two things at the moment. I've seen a similar issue to this on a friends 03 plate Peugeot 407 hdi and you wouldn't believe what was causing it. The trouble is that I'm not too sure if the C5 has the same set up particularly the crankshaft and pulley's. You could ask the technicians this question.

[Ronin]

Ok I've checked and Citroen share the same parts with Peugeot for both hdi models.

 

Three words, one part..... D.M.F. or dual mass flywheel....

 

It causes the impression of clutch slip when it is on its way out even though the clutch is healthy.

I rang Paul, my m8 with the same issues on his 407 2.0 hdi and he told me that :

 

"It took the peugeot main dealer tech's four rebuilds, four timing belts, one waterpump, four rollers and two tensioner assemblies before they realised what the problem was and still they were adamant the clutch was ok".

Does this sound familiar?

He went to an independant peugeot mechanic and he diagnosed the problem right away. the DMF was replaced as well as the crankshaft pulley as a precaution and he has had no further issues.

 

The DMF was lagging through slippage , thus slipping and increasing the crankshaft speed and what is connected to the crankshaft? Exactly... the bottom end pulley that turns the timing belt, the belt was therefore trying to jump the teeth to keep the timing correct and bearing in mind that the weakest link in all this is actually the belt, it then comes as no surprise for it to shred.

 

Ask them to check the DMF. A replacement solid flywheel can be obtained from Valeo for £200..ish. Apparently these are much better and offer smoother gear changes and of course prevent further timing issues.

 

Thank my m8 later ;) Lord knows it cost him enough to find out.

[Guest PeterHartley]

Ok I've checked and Citroen share the same parts with Peugeot for both hdi models.

 

Three words, one part..... D.M.F. or dual mass flywheel....

 

It causes the impression of clutch slip when it is on its way out even though the clutch is healthy.

I rang Paul, my m8 with the same issues on his 407 2.0 hdi and he told me that :

 

"It took the peugeot main dealer tech's four rebuilds, four timing belts, one waterpump, four rollers and two tensioner assemblies before they realised what the problem was and still they were adamant the clutch was ok".

Does this sound familiar?

He went to an independant peugeot mechanic and he diagnosed the problem right away. the DMF was replaced as well as the crankshaft pulley as a precaution and he has had no further issues.

 

The DMF was lagging through slippage , thus slipping and increasing the crankshaft speed and what is connected to the crankshaft? Exactly... the bottom end pulley that turns the timing belt, the belt was therefore trying to jump the teeth to keep the timing correct and bearing in mind that the weakest link in all this is actually the belt, it then comes as no surprise for it to shred.

 

Ask them to check the DMF. A replacement solid flywheel can be obtained from Valeo for £200..ish. Apparently these are much better and offer smoother gear changes and of course prevent further timing issues.

 

Thank my m8 later ;) Lord knows it cost him enough to find out.

 

 

 

 

This does sound really helpful; I've discussed it with my (independent) Citroen/Peugeot mechanic & he mentioned an old problem with Peugeot turbo-diesels that sounds familiar although back-to-front. They had a solid prop shaft which meant in certain situations the back (driven) wheels would be going faster than the engine and this would mean the drive accepting restrictive forces against the action of the engine...............failed at the weakest point (cam belt) The car is now back on the lift for deeper analysis and I'll let you know what transpires. Thanks for all the interest.

[Ronin]

This does sound really helpful; I've discussed it with my (independent) Citroen/Peugeot mechanic & he mentioned an old problem with Peugeot turbo-diesels that sounds familiar although back-to-front. They had a solid prop shaft which meant in certain situations the back (driven) wheels would be going faster than the engine and this would mean the drive accepting restrictive forces against the action of the engine...............failed at the weakest point (cam belt) The car is now back on the lift for deeper analysis and I'll let you know what transpires. Thanks for all the interest.

Hey m8, you are more than welcome. We are all here to help each other with little bits of info.

 

On a related note the crank pulley has some kind of anti-vibration rubber damper securing system which can peel away with time. Paul(screwloose) had posted some info on honest john site about it.

You may find interesting.

Paul is like a trainee doctor when it comes to mechanical advice, He reads it or experiences then thats all the advice he can give lol... I think you will get the jist of what he is trying to say though

http://www.honestjohn.co.uk/forum/post/index.htm?t=62929

 

He hopes you get it sorted m8.

[Guest PeterHartley]

Hey m8, you are more than welcome. We are all here to help each other with little bits of info.

 

On a related note the crank pulley has some kind of anti-vibration rubber damper securing system which can peel away with time. Paul(screwloose) had posted some info on honest john site about it.

You may find interesting.

Paul is like a trainee doctor when it comes to mechanical advice, He reads it or experiences then thats all the advice he can give lol... I think you will get the jist of what he is trying to say though

http://www.honestjohn.co.uk/forum/post/index.htm?t=62929

 

He hopes you get it sorted m8.

 

 

 

Update Thursday 29 05 08:

the cam belt has now been replaced (the last one was shredded again, just like before) and once again the direct damage seems to have been limited to the rocker assembly (only 5 rollers this time) The engine has run OK on test for a while so the investigation continues as to what caused it all. No other obvious culprit found yet so we're going ahead with a clutch replacement (losing the DMF and fitting the 'traditional' conversion kit instead.

Watch this space (fingers crossed)

[Ronin]

Update Thursday 29 05 08:

the cam belt has now been replaced (the last one was shredded again, just like before) and once again the direct damage seems to have been limited to the rocker assembly (only 5 rollers this time) The engine has run OK on test for a while so the investigation continues as to what caused it all. No other obvious culprit found yet so we're going ahead with a clutch replacement (losing the DMF and fitting the 'traditional' conversion kit instead.

Watch this space (fingers crossed)

 

I hope you get this sorted m8, I'll keep my fingers crossed too. I can't emphasise enough how important it is to get the cranckshaft bottom pulley thoroughly checked too. I spoke to my dealer service manager (Croxdale Citroen) and threw a few questions his way regarding this issue.

I just wish all Citroen service managers were as approachable as he has been.

 

Obviosly he started by saying "without looking at the car"

He too has seen this problem twice on C5's and both times it has been the DMF flywheel and bottom pulley. The flywheel puts undue pressure on the anti-vibration damper section of the crankshaft bottom pulley. One case he had seen the rubber damper seperated , the other case it looked fine but they changed it as a precaution. "That is assuming it is the same issue of course"! he gave an all knowing wink at the end of his comment.

He also said probable causes to these falures were down to:

 

1. too many fifth to third gear changes and booting it puts pressure on the DMF at some stage of the cars life. leading to excessive play.

2. Riding the clutch as one owner was renowned for it after going through 2 clutches on a his previous C3 in 40,000 miles.

3. Not lifting off the accelerator fully during gear change (the same owner lol)

 

I wouldn't have deemed it important as I can imagine how much money this is costing you but now now knowing what happens in these instances I would feel uncomfortable not advising about the possibility.

Let us know the outcome m8 and I wish you luck.

[Guest PeterHartley]

I hope you get this sorted m8, I'll keep my fingers crossed too. I can't emphasise enough how important it is to get the cranckshaft bottom pulley thoroughly checked too. I spoke to my dealer service manager (Croxdale Citroen) and threw a few questions his way regarding this issue.

I just wish all Citroen service managers were as approachable as he has been.

 

Obviosly he started by saying "without looking at the car"

He too has seen this problem twice on C5's and both times it has been the DMF flywheel and bottom pulley. The flywheel puts undue pressure on the anti-vibration damper section of the crankshaft bottom pulley. One case he had seen the rubber damper seperated , the other case it looked fine but they changed it as a precaution. "That is assuming it is the same issue of course"! he gave an all knowing wink at the end of his comment.

He also said probable causes to these falures were down to:

 

1. too many fifth to third gear changes and booting it puts pressure on the DMF at some stage of the cars life. leading to excessive play.

2. Riding the clutch as one owner was renowned for it after going through 2 clutches on a his previous C3 in 40,000 miles.

3. Not lifting off the accelerator fully during gear change (the same owner lol)

 

I wouldn't have deemed it important as I can imagine how much money this is costing you but now now knowing what happens in these instances I would feel uncomfortable not advising about the possibility.

Let us know the outcome m8 and I wish you luck.

 

 

 

Update 02 June:

Just got the car back & hoping this may be the end of the story. When the DMF came out there was 30mm of rotational play between the inner/outer sections where I understand the tolerance is only 10mm. So it looks like we may have found the culprit. If the clutch fails again in future (100Kmiles?) at least this time it shouldn't take the engine out with it as the car now has a 'traditional' conversion kit fitted. As a side benefit I have a clutch that is lots lighter to operate.

I don't know whether the crank pulley was involved but my mechanic said there was no evidence of any play anywhere other than the DMF. Irritatingly, the originial clutch plate still has stacks of wear left on it so if it hadn't been for the DMF I'd not expect to have been in this position for thousands of miles yet......

I'll be writing to Citroen about this little episode & the cost incurred. Somehow I think my correspondence is unlikely to be the last they'll hear on the subject and we can expect to see C5s coming back to base in droves with the same problem.

Incidentally I now hear that Renault also have a DMF design that has caused similar problems but they seem to be doing the decent thing and recalling affected models for a free upgrade.

Thanks for all your help; couldn'y have done it without you

P :)

[Ronin]

Update 02 June:

Just got the car back & hoping this may be the end of the story. When the DMF came out there was 30mm of rotational play between the inner/outer sections where I understand the tolerance is only 10mm. So it looks like we may have found the culprit. If the clutch fails again in future (100Kmiles?) at least this time it shouldn't take the engine out with it as the car now has a 'traditional' conversion kit fitted. As a side benefit I have a clutch that is lots lighter to operate.

I don't know whether the crank pulley was involved but my mechanic said there was no evidence of any play anywhere other than the DMF. Irritatingly, the originial clutch plate still has stacks of wear left on it so if it hadn't been for the DMF I'd not expect to have been in this position for thousands of miles yet......

I'll be writing to Citroen about this little episode & the cost incurred. Somehow I think my correspondence is unlikely to be the last they'll hear on the subject and we can expect to see C5s coming back to base in droves with the same problem.

Incidentally I now hear that Renault also have a DMF design that has caused similar problems but they seem to be doing the decent thing and recalling affected models for a free upgrade.

Thanks for all your help; couldn'y have done it without you

P :)

Your welcome Peter, anytime m8 ,I'm just glad you found the culprit.