Make sure that the electric cooling fans are working properly, that the
coolant has the proper mix, and that the timing belt is not beyond its
replacement interval.

Check to see if coolant level is being maintained.  If not, you may have
leak in radiator seam.  Check along edge of top/core seem for evidence of
fluid leak.

Leak causes loss of pressure which lowers boiling point and allow fluid to
boil off.

Happened on my SC400 a few years back.

Xplant

Well if you got new

-coollant
-new thermosta
-i would check the cooling fans and see if they come on after
-the vehicle is warmed u
-also change the rad cap a faulty rad cap can cause overheating

if its still overheating i would take it to a shop that carie
a coollant analizer specifically made to check combustable gases in coollant
that will tell you if you have any small head gasket leakes ocuring
in your case lets hope not.  if the head gasket is fine on the car then i would
suspect you have a partially clogged radiater. ok but your wise to take it in
because that overheating not only overheats an engine but also can overheat
the automatic transmission as well Oh ye
since there are bottom rad coolant lines that run t
the automatic transmission for coolling it
if the tranny doesent get enough supply of coollant circullating
it or that coollants  temperature is way to hot to cooll it. you can bet
your gonna start doing some harm on it and shortening its life span

--
johnin