Just had my timing belt, rollers and tensioners changed at 47,000 miles after noticing some rattling noises which turned out to be a worn bearing which would eventually lead to the belt slipping. This is on a 1.6 16V (X16XEL). Thankfully this was covered under Network-Q.
What the service advisor told me was that although the official timing belt renewal interval is 80,000 miles on my model (1998), they recommend 40,000 miles instead. Even Vauxhall shortened the interval to 40,000 miles for the 2001 model.
I then looked through the newsgroups and forums and found a lot of problems with the plastic rollers on Mk3 Astra 16Vs (1.4 and 1.6) failing prematurely (30,000 miles or so). Is this still a problem on the Mk4s? How were the rollers redesigned?
It does seem its still a problem. Unfortunatley Vauxhall have never got it right. The last engine course I went on before I left the Vauxhall fold the instructor told me Vauxhall had admitted defeat on that on and decided it was a fundimental design fault of the engine due to a fixed tensioner.
I quote "The tensioner works fine when the engine is under load but on over-run any belt slack is transfered to the other side of the belt where there is no adjustment and it damages the rollers causing failure."
Hmmmmm I smell something
The main reason I left Vauxhall was because I got fed up with doing cylinder head rebuilds. I have been working on VAG for over two years now and have done three heads in that time, used to do that a week at Vauxhall.
Thanks for the info. Doesn't sound very reassuring, maybe that's why Vauxhall halved the replacement interval. So in other words there's not much that can be done apart from replacing the belts, rollers and tensioners at regular interval and a lot of praying
Which engines were the ones that needed rebuilding though? I seem to get the impression (from on-line sources) that the pre-ECOTEC engines were more bomb-proof - was that the case when you were there?
All 16v engines are likely to suffer major head/valve problems if the belt fails because two or more valves will be left open when the pistons come up to the top. This is due to the angle of the valves !
Vauxhall 8v engines are less likely to suffer damage because the valves are in line with the pistons but the forces on the lifters (lash adjusters) can split the cylinder head so they're not bomb-proof.
It seems that Vauxhall and their dealers are now recommending cambelt change at 40,000 miles for all models, regardless of original recommendation.