-----Original Message-----
From: Gilles Gallant >Subject: Synthetic oil

>  -If I use the synthetic oil should I use the 5w30 or another grade?
  Use Castrol 15-50

>  -Should I take some precautions prior to change it or to run the engine
after the change.
No

>  -Should I flush the engine with some special liquid before put synthetic
oil.
No

>  -May I use ordinary oil with synthetic one?
Yes in fact, what I do, is use 1 liter. of  W15-50 and the rest regular
20-50.... then I top up between changes as needed with more 15-50.... that's
why they sell the blended synthetics... even some synthetic will cause the
oil to stick to metal better and stay coated.