Technical Seicento sporting coolant problem or not?

[RvpCro]

Hi I just recently bought little cento, and It wasn't in a great condition, but it was working, and still it is. I changed rocker cover gasket, oil, oil filter, air filter, brakes and more.. but one thing I didn't do, I didn't tell my mechanics to flush the system, and put antifreeze in. However since I've got a car, I notice when car is in idle, for more than 5 mins, fan goes on, since I don't have indicator showing is my engine overheating I really don't know is this big problem or not? and as well I did open reservoir and inside is really bad color, brown fluid. As I did a bit of research on google I think its rust and everything inside, and it needs a good flush. But my question is, is that dirty fluid inside making my fan going on all the time? or is that normal? I was driving car yesterday around 150 km, but as soon as I stop on traffic light or similar, fan starts.

Heating works normaly, it takes him not more than 3-4 min to start heating.
Cooling works normaly as well.

and one last question, is it hard to flush system? can I do it my self? do I need any chemicals for flushing?

Thanks.

 

[purf]

Fan coming on like that is normal. Color of coolant is also pretty normal when it gets old. It would be good to change the coolant and flush the system. All you need is a hose pipe and to disconnect the radiator or thermostat ideally as the thermostat will be closed when engine is cold.

The radiator fan might come on a bit quicker If the radiator is old and less efficient.