here's the thing about subaru engines, 90+.
the cost to split the case and do a proper rebuild from the crank up is more than the cost of swapping in a good used replacement engine.
so driving it until the engine ''dies'' is not a problem. although it could be inconvenient when / if it dies.
drive it until it dies and then swap in another engine. depending on the cause, it may take a long time.
i bought a 97 outback with ''bad wrist pin'' for cheap because i had an ej22 engine waiting to go in and i wanted to take advantage of the ''spare engine''. i drove the ''bad engine'' 40k miles and then sold the car. in my case it was piston slap.
on the other hand , you might want to check the valve clearances. i'm pretty sure you can adjust them in the drive way without special tools.
Last edited by johnegg; 01-26-2013 at 08:20 PM..