T4 TDI Woes

[gecko2k]

That would interest me as well. I thought also it was every 120.000kms or every 4 years.

[Bug_racer]

That would interest me as well. I thought also it was every 120.000kms or every 4 years.

Its every 2 years or 60k km . The interval was changed around 2001 after a string of snapped timing belts .

[Sunny43.5]

So by my calculations the second belt has failed at only 50.000 kays after it was replaced , I would be seriously asking the reputable "VW" mechanics why it has happened when I changed my sons T4 engine 2.5 petrol I fitted a new belt whilst the engine was out . The most important part as I recall is setting the tensioner correctly because if its fitted too loose it could jump a tooth or two if its fitted too tight it would obviously wear prematurely and possibly break ? . Did the mechanics fit a genuine belt or a substitute , this is a bit suspect to me as by rights you should have got at least another 50.000 out of this belt . As a final I did find out that the T5,s with 2.0 petrol were suposed to be done around 60.000 mine was done at around 100.000 so I must have been lucky it did not fail .

[tdi]

So by my calculations the second belt has failed at only 50.000 kays after it was replaced , I would be seriously asking the reputable "VW" mechanics why it has happened when I changed my sons T4 engine 2.5 petrol I fitted a new belt whilst the engine was out . The most important part as I recall is setting the tensioner correctly because if its fitted too loose it could jump a tooth or two if its fitted too tight it would obviously wear prematurely and possibly break ? . Did the mechanics fit a genuine belt or a substitute , this is a bit suspect to me as by rights you should have got at least another 50.000 out of this belt . As a final I did find out that the T5,s with 2.0 petrol were suposed to be done around 60.000 mine was done at around 100.000 so I must have been lucky it did not fail .

Belt was done by Volkspower hence the reason I took it back there.
I was told by them that belts rarely fail and that it could have been due to a bearing seizing up.
With this sort of thing, I imagine after its failed it would be hard to diagnose the actual cause of failure.

In answer to a previous post, I had slowed right down to about 10kms and was turning into a driveway when the belt failed so I was hoping this would have minimised engine damage.
Not sure whether an original or after market belt was fitted but the cost was $66 in 12/09

[Sunny43.5]

Sounds to me like you should be getting this "bearing" story checked out I may be wrong but I cannot remember the belt actually going around any part that has a bearing that could cause it to break , some one correct me if I am wrong .

[jfoldbar]

i know on a mazda van i used to have, mazda specs were "belt every 100k and tensioner only if needed". i found out the hard way that the tensioner must be changed at 100k regardless if its ok or not. luckily no damage for me though, just broken down. i wonder if a similar thing could have happened here. perhaps this "bearing'' should be changed at 120 or 60 (whatever specs say) regardless of its condition?
if a failed bearing caused it to snap, regardless of valve or cam condition this culprit bearing could still be found. but whether they want to find it may be a different story as it may show liability.

[tdi]

i know on a mazda van i used to have, mazda specs were "belt every 100k and tensioner only if needed". i found out the hard way that the tensioner must be changed at 100k regardless if its ok or not. luckily no damage for me though, just broken down. i wonder if a similar thing could have happened here. perhaps this "bearing'' should be changed at 120 or 60 (whatever specs say) regardless of its condition?
if a failed bearing caused it to snap, regardless of valve or cam condition this culprit bearing could still be found. but whether they want to find it may be a different story as it may show liability.

checked the invoice when the new belt was fitted and the cam belt tensioner roller was also replaced.

[Sunny43.5]

Still interested to know what part failed that caused the belt to break .

[jets]

With this sort of thing, I imagine after its failed it would be hard to diagnose the actual cause of failure

There are a couple of bearings in there. Inside the tensioner & the waterpump. If they haven't thrown them away it would be easy to see if bearing failure was the cause of belt failure. The tensioner housing can also break & is sometimes caused by trying to turn the tensioner the wrong way at installation.
Re sunny's comment about the tension in the tensioner it's only a matter of lining up the pointers at installation, turning the crank a couple of turns & checking that they are still in line. You can also check this setting some time later to see if all is well.
I have also read where a failed harmonic balancer can bring the whole house down.
Another guy had the crankshaft bolt break, the harmonic balance pulley went rolling down the road. I suspect someone didn't know or care that it is a stretch bolt, one use only. There are plenty of people that don't use the proper tools & use a rattle gun[she'll be right mate]
It's also possible to remove the top guard & have a look at the condition of the belt although I have been told that sometimes they just break & there are no evidence beforehand of what's about to happen.