T4 TDI Woes

[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.

[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.

[Sunny43.5]

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

[jets]

Me too.

[Seano]

I'd work on the assumption that it was the water pump since that is what seems to be the killer based on comments on the interweb over the years. I'll even wager it was the original pump. Current recommendations for the 2.5 TDi are belts (there are two on my ACV engine) and tensioners every 60K and water pump every 120K.

Mine are getting done on Tuesday.

Parts wise I was quoted about $120 ex GST for the pump and $330 ex GST for the timing belt kit...both from the dealer. Bursons gave me a similar price (a bit cheaper for the pump). Throw in coolant and about 7.5 hours labor and the dealer bill is looking at $1,400...