The simple answer is to use Mobile 1 0W40 sometimes labeled European and meeting the ACEA3 standard.
Other options approved as of 2006 are listed here EngineOilsApprovedbyPorsche2006.pdf
There is a later April 11, 2007 edition of this TSB and there may be even a 2008 version by now.
Anyone who has the later ones, please send it to me so I can update this.
But these are just fine for 986s.
Porsche reviews "approvals" every 2 to 3 years. So an oil approved today would be reviewed, if requested by the manufacturer, in 2-3 years. I have no idea if this request for approval is accompanied by a payment by the oil maker to Porsche. Wouldn't be surprised.
My personal take...
- any 0W40 synthetic oil meeting ACEA3 will be fine.
- If you are in an always warm climate (40 F plus year round and no ski trips) then synthetic 10 or15 W40 meeting ACEA3 is OK. (especially if you are having oil leaks) though you may hear lifter noise on cold startup as the reason Porsche switched to 0W40 weight oils in 2002 was to cure this complaint. Earlier Porsches had come with heavier weight oils.
I have heard of people with oil leaks switching to the heavier weight oils (10W50, 15W50) and the oil leaks stopping.