At 11:56 PM 4/8/2001, John Rodgers wrote:
>temperature and allow the coolant to begin to circulate sooner after a
>cold start. Seems to me that after the engine is warmed to standard
>operating temperature it doesn't matter. Hot is hot.

"Standard operating temperature" is what the thermostat controls -- it
opens progressively to let more and more cooler water in from radiator as
needed to maintain proper engine temp.  If the thermostat gets to fully
open, then with increased load system temp rises until the fan starts and
provides additional radiator cooling.  So within broad limits, an engine
with an 80C thermostat will run about 15F cooler than one with an 87C
thermostat -- up until the time that the thermostat is open completely.  By
the time the fan comes on they are both at the same temperature because now
the fan is controlling the temp.

As to whether it's a good idea to run a cooler thermostat, that's a
different question that I can't answer.  Too cool can be as bad as too hot
sometimes, and for efficiency the hotter the better.  People have been
mumbling for years about ceramic engines that would run red hot...

david

David Beierl - Providence, RI
  http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"