a design defect can be something not safety related - say, a right windshield wiper on left hand drive E53 (I am not familiar with layout of the RHD wipers) - while the left wiper can be lifted away from the glass, the right wiper can not while the wiper is in parked horizontal position...
has nothing to do with safety but makes no sense, and thus, I would consider this an oversight from the design engineers, where one team designed the wipers that can be lifted, and the other team designed hood that prevents the right wiper from being raised...
same with those valve seals - while it is not expected that something will outlasts the pyramids (gee, can i get over those pyramids?!!!
),
it is clear that something was not thought through... this is one of the reasons the manufacturers participate in races - race on sunday, sell on monday (or something to that effect)... they test and AGE their ideas on race engines running at 18000 RPMs and then move the ideas to the production engines... as a design engineer, they should know the properties of the materials used, if they break or bend under load, if the mineral oil corrodes or lubes the material, if sulfur in local gasoline destroys the internal guts of the engines (remember the V8 from mid-90s? the Alusil block? they were replacing the engines at that time due to the fact that they overlooked the KNOWN sulfur issue in the US petrol/gasoline)
and as far as safety goes... losing a vital component, such as engine going at traffic speed, and thus losing the power steering, the power brakes and the ability to safely command the vehicle due to UNEXPECTED mechanical failure of a major component... that is a safety issue... I am talking about those guides of mine on the M62 motor... And while you can blame me for changing oil every other christmas, and totally ignore the maintenance,
the sheer number of consumers with the same problem points to one common denominator, the design flaw in the engine... a piece of plastic inside an internal combustion engine - even sound of it does not make sense... and if the plastic component would have lasted, nobody would even talk about it but since it seems to be a weak link, we are talking about it... maybe metal guides would not be appropriate, but neither would be a wooden stick... or plastic... so, as engineers, they should have come up with something for those guides... or, abandon the particular design that calls for those guides... we are paying them to be experts in what they do, not amateurs...
I am not litigating this issue, i am not a lawyer, i am a technician, and while i admire many technical advances of the BMW engineers, i think turning a blind eye to an obvious problem does not serve their image well... and certain percentage of their price tag comes from an image - hey dude, what you drive? a Yugo... and you? I got a bimmer!... whose got a better image?...
and nobody expects a freebee - like with the cluster replacement, there was price for the part and comp'd labor... or combination thereof... or, like with Alusil engines, the whole thing was replaced... granted, with N62 being in almost all V-8 BMWs (minus the M cars) made from 2002 to about 2011 (is that right, BigBlack??), that is a lot of engines to replace... nobody will expect that... but coming with an improved part might be a better solution - i've heard that the simple valve seal replacement yields the same blue smoke in another 80,000 miles... for me, 80K is only 4 years of ownership... about 3.5 years... or so...