I'm running on full syn with an engine that has done 116K km in the last 5 years. It is wrong to say that old engines cannot use full syn. The advise is that if an old engine and has never used full syn before, then it is not advisable to change and it might dislodge the old mineral oil from the seals and cause a slight leakage.

So the advise here is, if the car has never used full syn for a long time, then it is not advisable to change.

This post has been edited by sleepwalker: Jul 11 2008, 02:49 PM