Peter as I understand it, wear and tear is not covered, only manufacturers defects.
Over time it has been reported that circa 3% of flat sixes from the 996 to the 997.1 could suffer intermediate timing shaft bearing failures, a situation which can apparently render an engine as scrap, even at car park speeds. If true that may have encouraged Porsche to initiate the extended warranty scheme back then..?
I suspect the terms and conditions of the insurance based Warranty relative to Porsche only parts and servicing may well have offset the cost of replacement engines etc..?
i.e. the O.E. manufacturers AGM battery for a 991 can be bought at a considerably reduced cost from trade sourses, however without the additional Porsche label, apparently the warranty may become void...?
Pretty sure that the terms and conditions of the warranty are available to any who purchase a pre owned Porsche via the official network.
