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Question:
Oil Change Interval for Air-Cooled Engine
I recently discovered the new ILSAC GF-4 specs and realized that the Castrol GTX motor oil I have been using does not have the protective phosphorus and zinc like it used to and that my car needs. I meticulously care for my 1989 Porsche 911 Carrera. It is a daily driver with 148K miles (I put about 12K miles per year on it). Because of this discovery I am about to switch to the Porsche recommended Mobil 1 0W-40 synthetic. Being an air cooled engine it takes almost 13 quarts of oil and each oil change is considerably more expensive with Mobil 1. (Wal-Mart has the lowest price for 0W-40 but they have an 8 quart limit for some reason.) Questions: Should I use the 0W-40 or the High Mileage oils that are not of the same weight? (I live in Phoenix where it gets VERY hot during the summer) And what should the oil change interval be? I am thinking of changing it from 4 times a year to twice a year.
-- Kenneth Huff, Phoenix, AZ
Answer:
Your engine will be protected with either Mobil 1 0W-40 or Mobil 1 15W-50, which should work for you at the intervals you mention.
