Oil viscosity

[rockyfeller]

Maybe this is a played out question, but I have to ask....what's the best grade oil (conventional not synthetic) for a 540ia driven in the NYC climate? I was going to go with 0W40 Mobil 1 as many of you, but decided to stay conventional instead. Oil change places usually throw in 10w30 but I never assume they know what they're doing.. I used 10w40 last time, is this smart? What's the best to use?

[tim]

It's a touchy subject. But in NYC you should definitely be running synthetic. My recommendation would be 15w50 Mobil1 in the summer and 0w40 in the winter. If you had to go with only one- go 0w40.