[arucano]

The shop I use was asked to go through the cooling system before I went to O'fest at Laguna Seca. The following items were replaced in several phases, paying several times for some of the same work:
replaced Radiator, Fan, Fan Clutch, Electric (condenser) fan, radiator shroud, thermostat, expansion tank, water pump. Cooling system was pressure tested.
The car does not overheat if started and left to idle. I drove the car home and it got hot as I reached home (10 miles).
The 4 days I drove the car and checked the coolant level every morning and have not lost any coolant. Yesterday, it started to "overheat" again. i have been monitoring the coolant temperature with the OBDII scanner (I use a C110). The radiator outlet temperature remains fairly constant and the OBDII temp swings between 190 and 225 when driving slow and to a lesser degree on the highway. When it goes bonkers, it swings up to 235/240 and will drop down to 180 at times.

just performed some further checks. The radiator outlet temperature increases to 200F when the engine run too hot. The electric fan is running at full speed when it gets that high. I cant find my remote temp gun to verify these temperatures however.

EDIT: 2003 530I sport standard with 225000 miles


I am out of ideas and am seeking your wisdom.

Chet