Timing Belts & Antifreeze, etc.

[wolff at turboquattro.com]

> IMO, its a fair probability that the back side cracking you show did
happen
> in the last 8K miles, caused by a stiffening/failing idler bearing.
Nope. Idler was not changed at that time (I didn't do the job), and yet when
I did go in for a water pump later, the idler was fine. (I changed it
anyway, wasteful I know).

> Further, IMO and the tensile testing results of similar 150K belts, this
is
> a superficial appearance problem, not an indication of impending failure.
> The newer, '90s on, radiused tooth profile TBs are far superior to the old
> trapizoidal tooth profile belts of the '70s and '80s, why the car mfgs
have
> increased their conserative TB change intervals up from 60K to 90 and
120K.
> Just keep them tight!
Could be, but I'm not banking on it.

> > BTW, I have seen teeth strip out of an externally perfect looking belt,
so
> > just because it looks good, does not mean it is good.
> Such a TB failure is only caused by problems external to the belt, such as
a
> piece of distributor drive gear getting caught between a cam lobe and
> follower, and is independent of previous belt life.
Wrong. It _can_ be (and maybe usually is) caused by external problems, but
in the case I was citing it wasn't. The belt was just old. I put a new belt
on and everything was fine. Motor ran many thousands of miles afterwards
with no problems.
Phil Payne used to say to check the inside of the belt for cracks by bending
it in a reverse radius to get a true indication of it's condition.
Just my $.02
Wolff