Having owned 30 plus aircooled 911s, I recommend you do as porsche advise. 12000mile oil changes. Using the oil the engines were designed to use. Mineral oil, NOT modern synthetic oils that are designed to lubricated modern engines. From my experience using synthentic oil will reduce oil pressure and causes your engine to spring oil leaks. Synthetic oil is alot thinner when hot. 3000miles oild changes in an aircooled 911 is frankly defeating the object of owning a classic 911. The joy of owning such a car is its relatively low cost servicing. If you enjoy trashing many litres of perfectly good oil every 3000miles, then i recommend you buy an old Ferrari. For a porsche specialist to tell you otherwise, they either don't know what thye are talking about or are trying to rip you off.
