Date: 8 Jul 2002 20:38:04 -0700 From: doctorbrownnopsaml.com (D J Brown) Subject: SAAB 900 cracked gearbox casing at oil sump drain
Here's an extensive question about SAAB's gearbox casings (pardon the length): I have a beautiful, red, 60,000 mile 1990, SAAB 900 Turbo convertible with a SAAB service history for the first 8 years. It's been well looked after for its entire life. I've had it a couple of years (and about 12,000 miles). A really nice motor, of which I am justifiably proud. It spent last winter in a garage and I recently decided to put it on the road for the summer. I took it to have an MOT (the UK road worthiness certificate) which it passed without problem. The garage then agreed to change the oil. They rang me to tell me that in so doing they noticed that the oil sump drain had cracked. This is a problem that is known to occur when overtightening the sump drain plug (e.g. see http://www.thesaabsite.com/900old/900&79to94drainplugs&washers.htm and previous posts in this group e.g. http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=3643180e.0%40news1.mcmail.com) Anyway given the size of the cracks and construction of the power unit, the only sensible repair is to replace the gearbox with a reconditioned unit at vast and unreasonable expense. So, I decided to employ an automotive consulting engineer and metallurgist (such people exist) in order to report on the failure mode of the casting - convinced as I was that the car had been manhandled by the garage. However, having examined the metal at various magnifications, his conclusion is that the drain had been fitted with a "helicoil" thread insert which had moved and, moreover, that the cracks that had occured were old and had progressed over time. However, the more insidious suggestion has been made that the weaknesses of the castings were a known defect in the manufacture of a series of casing around 1990 and this was a fault known to SAAB at the time of manufacture and that this helicoil repair was factory fitted in some models in order to overcome the known quality problems with the castings. OK so here, at last, is the question: Can anyone shed any light on the suggestion that SAAB procured poor quality castings, that they knew about this and fitted these helicoils at manufacure or ordered their insertion as a product "enhancement"? Any information relating to this - or stories of similar disasters - gratefully received. Yours in the red (but sadly not in the red car) D J Brown
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