On Jun 15, 10:48*am, DerbyDad03 wrote:
This question is about the decision process involved with replacing
the timing belt in a vehicle "now" or "later".

Let's not confuse the issue with cost or voiding warranties, etc.
Let's assume there is no warranty to deal with and that the cash is
readily available, both now and later.

Here's the situation a friend and I were discussing the other day:

The manual - and therefore the dealer - says the timing belt on his
vehicle should be replaced at 90K, which is right where he's at.

He called around to various repair shops for a price and multiple
places told him "I've never seen a timing belt go on that vehicle
before 110K. The dealers just want their money early. There's no need
to replace it at 90K." He was even able to "verify" that opinion on
the web.

OK, so let's say that you are planning to keep the vehicle for the
foreseeable future, probably well beyond 110K. That means that you
will need to replace the timing belt, probably in about a year, to be
safe.

So here's what I was thinking:

There's a pretty slim chance that you'll keep the vehicle for the full
life of the second timing belt. That would put you in the 220K range.
Even if you replaced it at 90K and it really will last 110K, that's
still pushing 200K.

Why would you wait until next year and not replace it at 90K? Even at
the dealer's "accelerated" schedule, you're good until 180K, by which
time you'll probably have gotten rid of the car, so why not be *extra*
cautious and replace it now?

Thoughts?

Depends on the valve design. On some vehicles it is possible to have
valve / piston interference if the valves are left open while the
piston completes it's cycle. On other engines it is not possible for
the valve and piston to colide no matter what their positions.

As you can imagine if your engine falls in the first category you can
have a whole lot of extra damage if the timing belt breaks. On a 100k
+ mileage engine it could be toast as the rest of the engine condition
might not justify that sort of repair.