Fryer:

That's how he got to be an old drunk, waiting for that first quart to trickle through!

Can-do:

Synthetic will indeed scrub up your engine internals -- the base fluid has considerable detergent power in it's chemical makeup. You will only run into trouble if the engine was run for extended milage on cheap oil -- any modern detergent oil will keep the engine pretty clean unless it is run until the detergent additive dies.

If you are concerened, pull the valve cover -- if there is any hard scale up there, it will float off and end up in the oil pump and filter. If there is only varnish, it will dissolve.

The only engines I've seen in the last few years with lots of sludge were one run with vacuum leaks (i.e. no air filtration) and/or run on non-detergent oil. I've heard of a few that never had the oil changed, just topped up -- had to punch a hole in the sludge to drain them! May be an exaggeration.

Leaks are a different story -- I personally haven't every had an appear, but I didn't use synthetic before I moved back from Canada -- all the cars I had leaked some, and I didn't see dumping expensive oil on the road. Some will leak more, some less with synthetic -- my 285,000 mile Chevy box van stopped using oil when I started adding Mobil 1 instead of Valvoline!

My presonal feeling is that if it doesn't leak now, changing to synthetic won't make it leak UNLESS you have bad o-rings in the oil recovery system sealed with varnish -- when the varnish is dissolved, they will leak, probably permanently. Gaskets won't usually leak (except the valve cover gasket, and that is easy to replace). Lip and rope seals won't, either.

You will get similar longevity with dino oil so long as you change it often.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!