Digger58 makes a good point about the fan. Someone here coined the term 'the silent killer'.
In normal operation the fan seldom comes on. If it does fail you may not be aware until the day the car overheats when you get stuck in a summer traffic jam.
As part of the annual service with the ignition OFF I check that the fan is free and then I disconnect the temperature sensor with the car running ( ignition ON will do it as well ) and the car should respond by putting the fan on within ten seconds and the idle speed will increase a little.
The most frequent causes I have seen here are seized fan and broken wiring between the fan relay and the ecu.
P.S. The fan can probably come on with the ignition OFF if the motor is hot enough. Best practice is to disconnect the battery before sticking you fingers near the fan. It may be plastic but can still do serious damage.
Yes, you are quite right.
But yearly checking the fan, will not give much guarantee, except for that one day you do it.
Changing the fan will to some extent give you a guarantee it works.
Every 5'th year, or... ?
I've had 3 HG blows.
One in the old Punto.
In only one instance, did the temp-gauge show the heating in advance, but it was the waves of steam, that told me, that something was terribly wrong.
With the Punto there was no rise in temp and not that much steam, until I stopped the car (due to the noise).
The fan worked perfectly !
BUT, if the car has been running hot at some point, then:
1. Fix the cooling issue (radiator, fan, collapsed hose, waterpump, coolant...)
2. Renew coolant and engine oil.
If the heating was more serious:
3: Have the heads done (incl. new seatings) and new HG and change the crankshaft-/pistonrod bearings.
4: Change the thermostat.
5: Change the waterpump (heated bearings...) and then the timing belt as well.
Never underestimate the destructive power of a hot engine !
I've met one engine, where heating made, that the pistons them self, could hardly be moved inside the cylinders.
Thanks all for joining.
I think that I'll stick with my list:
Weekly:
Check oil and COOLANT (level
and color)
Every 80000km (48000 miles):
When it's time to change Timingbelt and Waterpump,
also change Thermostat and Head Gasket !
IF your car runs hot, check the fan.
IF your car runs cold, check the thermostat.