Having had a squiz at the Peugeot owner's manual, it says something about the correct type and grade of oil being essential to the smooth running of the engine given the extended service intervals. I know that's true to a greater or lesser extent for all cars, but the handbook seems to make a big thing about it being really important in the 406's case.
My questions are:
a) what oil do people use
b) are Peugeot exaggerating?
According to the service book, the oil hasn't been changed for nearly 3 years

Thanks for any and all advice.