The same thing happened on my van too, after I replaced the exhaust.  I used
all new stainless nuts and bolts w/ anti-seize.  It has become habit to
check the bolts when I crawl under the van now.
Also, my brand new complete exhaust that I installed in May of this year
already has 2 broken brackets.  Not what I expected when I paid close to
$500 for all new exhaust, and it has started to fall apart in 6 months time.
bye,
Kim
85 GL

>From: Blake Thornton <thornton@MATH.UTAH.EDU>
>Reply-To: Blake Thornton <thornton@MATH.UTAH.EDU>
>To: vanagon@GERRY.VANAGON.COM
>Subject: Missing Exhaust bolts
>Date: Wed, 28 Nov 2001 11:29:26 -0700
>
>I climbed in my 84 van this morning and turned it on, and boy did it sound
>rough.  I figured it was just cold (it was probably 15 degrees F here in
>Utah this morning) and I figured the van needed to warm up.  Well, it
>sounded very rough the whole ride and when I got home I looked underneath
>and took a look.
>
>Where the collector pipes (attached to the heads) meet the next pipe (the
>pipe with the O2 sensor in it), there are four bolts (two for each pipe),
>and I only had one.  Somehow three of the bolts came undone!  I put a new
>exhaust gasket (it was missing where the bolts were missing) and put in
>some new bolts, but why did this happen?
>
>I recently put on a new exhaust system (less then a month ago), and I am
>fairly sure I tighten everything down good.  Just to be sure, I checked
>all the exhaust bolts and there were a few that were looser then I liked
>(so I tightened them up).
>
>What do you think?  Was I careless, or was the heating and cooling cycle
>on a new exhaust system enough to loosen the bolts?  Or was it something
>else?
>
>Blake

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