Chrysler Repair: 2002 PT Cruiser Radiator Fan replaced: thermo/sensor too?, upper intake manifold, thermo sensor

Question
I replaced the radiator fan on my daughters PT Cruiser. Should I replace the thermostat and engine coolant sensor ? Also does the upper intake manifold really have to be removed to replace the thermostat ... looks like there may be enough room to do it without removing it and the owners manual states that an anti-freeze with HOAT be used ... I have yet to find that type.

Answer
Hi Carl,
In general I know of no reason per se to replace the thermostat and temp sensor because you replaced the radiator fan. If the temp gauge seems to be staying in the 1/3-2/3 of full scale, and there is no apparent engine control issues as the engine warms from cold to operating temperature then there is no obvious reason to replace those items. Other than fan motor failure is there any reason for you to believe these other parts are at fault?You can get a free fault code readout at an Autozone parts store which would highlight a temp sensor problem, but there is no fault code for the thermostat except maybe the one for engine running cold for too long a time after start up. You could also check the resistance of the temp sensor which should run around 10-14,000 ohms when cold and drop to 700-1,000 ohms when warmed up.
I don't know about the issue of replacing the thermostat because I don't know which engine you are working with. So let me know and I can give you an answer. I haven't heard of HOAT, but I suspect it means the orange-colored type.
Roland