Originally Posted by BartStar
I have seen too many people in the past make the mistake of switching to a full synthetic after high mileage and they experienced major engine oil leaks, exhaust smoking, poor perfomance, not saying this will happen to everybody, but I wouldn't take the chance!
The oil debate will go on and on and on.........
Yes Syn will clean your engine.
46K is not High miles.......
SYn will not sludge like Dyno oil..
You can run SYn or Dyno oil to the Manufacturers recommended change interval, unless it is heavy use, then follow their intervals for that.
Dyno should be changed every 6 mo's or at miles. Reason being is it becomes acidic with time due to its very nature.
SYn can run the mileage regardless of time. It will not become acidic over time
People who have problems when they switch are usually the ones that have not done regular oil changes when using dyno and have sludging and excessive wear due to poor oil quality over a long period of time. When they put syn in it does clean the built up crap out, and the engine may exhibit some of the symptoms listed above.
On the other hand; If you have been doing regular maintenance there should be a nice clean engine to put SYn oil into with no ill effects.
I started using Syn oil in my old 85 Jetta with 300K+ mile on it. I did regular maintenance always. There was no change in oil consumption, leaking, etc.. In fact the SYN oil with all its additives seemed to help the old seals on that motor and there was less dripping, although there was not much to begin with.
Do your homework, make your own well informed decision, and drive happy.