Make sure the hangers are all in place.
There are many hangers that  the original exhaust have to support
the head pipes.  Head pipes crack because theses hangers are broken  or
missing.  The front head pipe on a 2.1L has a hanger in the very middle
of the engine
and right at the output flange.  I've noted that some head pipes
don't have the center support from the factory.  I guess they expect
you to use the original support.  The output flange hanger rusts thru
after a few years, and needs  re-welded to prevent cracking.
    The rear head pipe on a 2.1L has a  support hanger mounted on
the first muffler bracket.  I've found these both missing and rusted away.
     Last the muffer brackets and straps rust.

I curently have the worlds worst vanagon exhaust system.   I've patched,
welded,  and repaired this system for over 5 years.  The  flanges have
been so bad, that I've weled the entire system together as one.   In the
next month or so, it will all be history.
                                                                Joe W.
     Part of the PVA organization... over 100 strong........

Kim Springer wrote:

>Gang,
>
>I searched the archives and I can't believe I didn't turn anything up.
>
>I heard an exhaust leak developing, and lo and behold, both of my headers had cracks...big ones.
>
>Why did they crack?  Fatigue, heat differentials (is the temp between the manifold and cold air blowing buy under the car too much temp diff for the material), installed with too much stress initially?
>
>I never had one fail on any of my aircooled VW's.
>
>Anybody ever studied this?  Would it make sense to cover/insulate the new set?
>
>New ones on the way....
>
>KAS
>'89 Tri*#7 2WD White
>
>
>
>