I took my Impreza out this morning.  Some of the stuff I drove through was
grass and some was mud.  All of it was flat.  Afterwards when I parked I
noticed my engine was hotter than usual.  I thought this was ok because I
had been driving it hard.  I cleaned off the radiator and started to drive
home.  I noticed the engine was getting hot.  I stopped and saw the
antifreeze overflow was near empty.  I washed the car and got the radiator
good and I think I cleaned the undercarriage well.  I filled up the
antifreeze and sprayed water on the engine.  The antifreeze dropped to
between the hot and cool level.  The oil level was fine.  I thought all
was well because the heat stayed at the normal level for a while.  After
maybe 15 miles it started getting warmer again, but not as warm.  I rode
with the heat on high the rest of the way home and it got warm towards
home but stayed good overall.  Do I need to clean something else?  Is
there something I need to do?  Did I hurt my car?  Help, TIA.