Oil consumption

Q What is the appropriate oil consumption of a 2006 Porsche 911S (977) Carrera 4S 3.8 with 84,000 miles? The handbook suggests up to 1.5 litres per 1000km. The car is used twice a week and driven gently, never above 3500rpm on rural roads of about 30 miles. It produces some smoke on start-up up, but nothing afterwards. Because of the low mileage, it is difficult to say what the consumption would be if longer distances were covered, but I seem to have to top-up the oil regularly. I previously had a 911

3.6 with 40,000 miles and rarely had to top the oil between services. I always use Mobil 0W-40 fully-synthetic.

As you will know, this model can be affected by bore scoring and I wonder if this could be an issue. All four exhausts are clean and dry, and there is no soot or smoke on the left-hand side, which is normally a clue to a problem.

JE Knight

A 0W-40 is the preferred oil grade and I would certainly continue using that. As you do not have oil in the exhaust pipes, this would suggest that an undue amount of oil is not being burnt.

The 977 engines do consume oil in use, more by design than due to wear and tear. The engine is a high-performance unit and, as you mention, there can be bore scoring problems. Unfortunately, I have seen these engines fail and when they do it is quite dramatic.

As you obviously keep the oil topped up as required, you should hopefully ensure that your engine will continue without too many problems. Oil consumption of vehicles of the same make and model will vary. You have not mentioned how much oil you actually add, but up to 1.5 litres per 1000km (620 miles) is quite acceptable.