My 4AGTE runs between 90-93 degrees (this is reading off the Wolf hand set controller) without any problem. This translates to halfway on the dash temp gauge, and it stays there summer and winter long.
well if it gets as low as 80 when your driving it would have to be bloody cold outside seeing as the standard thermostat opens at 82c, general operating range should be between 84-90cish.
With the Wolf I also sit around the 90c mark but because of the size of my radiator i can drop as low as 86c and i set thermos to kick at 95c ( never gets there unless im sitting stationary for more than 10 mins in hot conditions ). Ive often wondered if the Wolf reads slightly high but have never got around to throwing the temp probe in there, also i measure my temp from the back of the head where the temp is slightly hotter anyway so it could well be accurate.