Technical Broken cam belt

[Stuart74]

I have a broken cam belt on a 2003 2.0 JTD Ducato based motorhome which has done 24,000 with cam belt replaced in March 2010 (10,000 miles ago). The vehicle is in the garage who say the belt has snapped due to something "locking up" on the camshaft. Can any one advise or give guidance on:
Could something break or "lock up" on the cam shaft to cause belt to break or is it more likely the belt broke first and then caused the "lock up"?
Also what is the recommended replacement intervals for cam belts on this engine with my usage?
The same garage had replaced the cam belt so I suspect they do not want to take on any responsibility for premature belt failure.
Thanks.

 

[Most Easterly Pandas]

The same garage had replaced the cam belt so I suspect they do not want to take on any responsibility for premature belt failure.
Thanks.

Its not about taking responsibility, its nearly 5 years ago it was changed and does very low mileage, it should have been changes about 2 years ago due to this!

 

[portland_bill]

As said above, garage is unlikely to blame.

If the cam seizes, it will cause the belt to break or jump teeth. Once the engine has cooled, the cam may now rotate, masking the seizure, but this would be evident when dismantled as the bearings would be damaged. Causes: overheating, or oil starvation.

If the belt breaks, pistons will hit valves, which will bend, then prevent the cam from rotating. This is possibly what is currently diagnosed.

Belts break due to age, contamination with oil, or occasionally ingestion of debris from the road. Plastic bags can be particularly dangerous for this. Twigs and other hard road debris usually leaves witness evidence, to help diagnosis, but plastic bags can disappear leaving everyone baffled.

The tensioners and idlers are just bearings and should be changed when the belt is changed. Seizure of one of these can cause the belt to break, but the belt should show signs of rubbing on its back where the tensioner has stopped rotating.

If the water pump is driven from the cambelt, these can also break the belt if the seize.

It is unlikely that the garage can be held responsible, but as it is dismantled to identify the state of damage and estimate the repair costs, all these possibles need to be checked to determine the root cause. Failure to rectify the cause will lead to another failure.

Good luck, and keep us posted.

 

[varesecrazy]

I have a broken cam belt on a 2003 2.0 JTD Ducato based motorhome which has done 24,000 with cam belt replaced in March 2010 (10,000 miles ago).
Could something break or "lock up" on the cam shaft to cause belt to break or is it more likely the belt broke first and then caused the "lock up"?
Also what is the recommended replacement intervals for cam belts on this engine with my usage?
Thanks.

what was changed along with the cambelt,
seized tensioner pulley would be my No.1 suspect,

In normal service , used most days the interval is probably @ 40K miles,

but if it's parked-up for extended periods, then corrosion plays a part with all exposed metal bearing surfaces,

( this is actually where a cam-chain is better- as it's all in an oily environment)

as
others have said the apparently seized cam could be a symptom rather than the cause,

Charlie

 

[rolopolo]

48 months or 72000 miles whichever comes first

 

[Pasty007]

Thats why I always go for the 3 Ltr. No cambelt to worry about.

 

[rolopolo]

Yes pays for itself the extra cost over time having a chain, especially the mileage I do lol

 

[CDK]

Another cause - not yet mentioned here - is excessive tension when the belt was replaced 10k miles ago. Most of the time an expert can determine the cause of failure, an overtightened belt looks worn over the whole length.

Many years ago the engine in my brand new 124 Spider blew up in city traffic after 3000 miles because the belt snapped. The dealer wasn't surprised at all: the factory supplied a new engine within a week.

My Ducato got a new belt this year. It became a very expensive operation because after 6 years in a coastal area removal of several parts was almost impossible due to corrosion, yet the belt with 60k miles looked like new.

 

[Stuart74]

Thanks to all for your very informative responses. I'm going to the garage next Monday when hopefully I'll find out more - and the cost of repair. I'll keep you all posted as to what happens.