hi
i'm thinking an oil change will help reach my mpg aspirations. it says in my haynes manual that it takes 5w40 or 10w40 oil. can i get away with using 0w30 oil ? its winter here at the moment. would an oil pressure gauge help? i take it would not be advisable to run lean with this new oil.
would a gear box oil change score me more mpg's than engine oil change? i have a manual, petrol engine.
thanks for your help
