playing kill by
AO Gold Member
Join Date: Feb 2005
County: Down in the Park
Re: Couple of questions from new 155 owner
the fan is only used when the normal cooling isn't adequate, usually when moving slow or standing still.
The thermostat IS regulating the the coolant temp, it's not an on/off switch, it starts to open gradually around 70°C and isn't fully open until 90-something°. If the fully open isn't enough the fans kick in...
Some cars have a coolant temp regulated by the ecu, but even in these cases there's a thermostat present, and the ecu just fools the thermostat by turning on a heating element inside (forcing the thermostat open at lower engine temp).
I haven't had the need yet to look at my 16v thermostat closely, but i think the difference might be oil/coolant heat exchanger, which might be not present on some models... though my 1.4 seems to have it...