hey listees,
        I have a concern with swithcing over to synthetic oils in my GL with 90k on
the engine.  I have looked at the benefits of using sythetics (easier on start
ups, adhears to moving parts, holds its viscosity at higher and colder temps,
less tar build up due to less waxes etc in petroleum based oils).  My question
is, and the concern is its "engine cleaning ability" the manufacturers speak
of.   My engine its all that old as compared to some of the listees, but with
this type of oil attack some of the tar/other residue that maybe/could plug a
gasket leak if there is a potential weak spot on it.  I currently use 10w 30
(cold vt weather) and change it regularly every 3000 miles ( sometimes
sooner).  The engine itself is in good order, no leaks of oil or coolant, I
don't know the compression (will get checked soon), however it does run a bit
warm when its been traveling a hightway speeds for awhile.
So, am i risking anything by switching over at this stage in the game or not.
I have read that some people swithced over, but when, and how is everything
going so far with the switch

any info as always is appreciated
jon 88 gl 90k
had the van about 1.5yrs