How do you know when to change timing belt?

[Paul Heneghan]

> From: "Martin W. N. Suryadarma" <msuryadarma at mail.wesleyan.edu>
> Hi all,
> I bought my 89 Audi 100 last year. It had 98k miles then, it has 108k
> now. How do I know when to change the timing belt? . . .

That's easy - you need to change it just before it snaps and allows pistons
to hit valves causing $$$$ of damage.

Before you send me lots of hatemail for my glib answer (and copy it to the
list to annoy lots of other innocent listers!), here's a more considered
response.  I think the time interval that Audi recommend is 60k miles.  Some
pessimists would go for 50k or even less.  I've heard of (and seen) ones
replaced at 120k where the belt still looked OK - thousands of minute
surface cracks, but nothing serious.

If you have no previous history of the car, you've got to do a Dirty Harry
on it - "Do I feel lucky".  It may have been done at 60k in which case
you're alright for another 10k miles.  It may have not been done at all
(highly likely in a car whose owner has 'lost' the service history) in which
case you might be minutes away from blowing up your engine.

I know what I'd do:  buy (from an OEM supplier, NOT Audi) a new belt, water
pump (and idler pulley if necessary), cam cover gasket, maybe even crank and
cam oil seals and also tool 2084 - the total would come to about GBP100.
Then I would do the job the next weekend.  If you lack the experience (or
strength to get the crank bolt off), get a tame mechanic to do it for you -
I think you're talking about a  two-hour job if you know what you're doing -
I usually take about four hours, most of which is spent tidying my garage so
I can find all my tools!

Search the archives for info on this job, particularly discussions about how
to lock the engine in the absence of 2084 and the tightening torque of the
crank bolt.

Paul