Re: 5KCST Harmonic vibration-help

["Sherry & Chuck Clark" <clark@rmi.net>]

> Date:          Fri, 26 Sep 1997 11:25:35 -0400
> From:          Don Hoefer <hoefer@jaxom.eng.pko.dec.com>
> To:            clark@rmi.net
> Subject:       Re: 5KCST Harmonic vibration-help
> Cc:            quattro@coimbra.ans.net

> 
> Chad,
> 
> > My '87 5k Tq recently had both 
> > motor mounts replaced but none of the exhaust was moved in doing this
> > repair. Everything seemed fine and then about a week later I noticed that
> > at exactly 1800 rpm, there is a harmonic vibration that came about.
> 
> I don't know how many models this applies to, but my Bentley says that
> the exhaust supports must be tightened when the system is hot.  Other-
> wise a rumbling sound may be produced.  These systems have rubber
> hangers on the rear (so no adjustment there) and are hard mounted with
> a bracket on the transmission (tighten here).  Changing the engine
> mounts would change the position of the engine.  Were the engine
> mounts tightened when the engine was idling?  If not, the position of
> the engine could be a little "off".
> 
> Don Hoefer
> '82 Coupe
> 
>  
      Thanks Don and to others that have suggested this. It didn't really
occur to me that yes I have changed the position of the engine-quite higher
than it used to be. I'll try this and let you know. Thanks again,

Chad Clark '87 5k Tq