I changed to synthetic about 1 week ago.  I used Mobil 1 15W-50 which was on
sale at Walmart for $18 and something, for 5 quarts.

So far I have seen no leaks at all but I have only done about 700 miles.
What I did see is that the engine ran cooler.  I was amazed !!
I used to run with the temp gauge needle on mid LED.  Now it runs with the
needle just below the LED.  That alone made a believer out of me.
Driving 75-80 mph with a/c in the Carolinas last weekend.  No trace of temp
increase, even driving hard up to the Blue ridge parkway....on the contrary.
Van is '91 Carat with 128 k.      I bought the van with an overheating
problem....can't find it !

Steve Cotsford
Columbia SC