Hi,

  I am seriously thinking of changing my ordinary castrol 20w50 oil for the Amsoil 5w30 synthetic oil.  Because I am not sure of the impact of this (except the $$$ one) I would like to have some feedback from the list about that.
  -Should I use synthetic (I don't care to pay some more money if it is better for the engine.)
  -If I use the synthetic oil should I use the 5w30 or another grade?
  -Should I take some precautions prior to change it or to run the engine after the change.
  -Should I flush the engine with some special liquid before put synthetic oil.
  -May I use ordinary oil with synthetic one?

  P.S.  My first language is frencg so, sorry for the english language mistakes.

  Thanks,

  Gilles Gallant
  1990 Westfalia
  Montreal, Quebec