Date: Tue, 14 Dec 2004 09:58:25 -0500 From: Fred W <Fred.Willsnospammyrealbox.com> Subject: Re: 9000 tensioner problem?
Richard Sutherland-Smith wrote: > We have just replaced the chains in my friends 1996 9000 Aero > Automatic. He is now suffering from a vibration at low revs which > smooths out to be unnoticable up the rev range. The chains were all > adjusted to TDC and the marks on the balance shafts and cams all lined > up, and were still lined up having rotated the engine a few times by > hand before we put the timing cover back on. We put a new water-pump on > and top engine mounts, replaced the two pulleys and belt, and > reconditioned the starter and alternator. I am wondering now about the > belt tensioner and would like to know how this goes bad and the effects > of it doing so please? > Does anyone else have any ideas to work on? Richard, My experience is that these engines *normally* tend to vibrate quite a bit at idle, especially with automatic transmissions when in drive. If everything smooths out at higher rpm (just above idle) it sounds like the balance shafts are probably OK. Are you sure that the vibes are abnormally high? Have you had an experienced SAAB mechanic look at it? What sort of upper engine mount bushings did you install? I know from experience that the urethane "performance" bushings increase the vibration at idle severely. BTW, I've never heard of a belt tensioner causing engine vibrations. -Fred W