Technical overheating

[AJ 96]

Hi

just took my car for its MOT and it started overheating on the way back
ive checked all the hoses and ive found out whats wrong, the fan isnt coming on, checked all the fuses
going to have a better look this afternoon, just wondering if any one has any ideas on what might be wrong

also all the hoses are hot and the heater works

thanks Alex

 

[Alfa Patch]

Is it a cinq?

If so maybe the fan switch in the rad

 

[David C]

Also, carefully check that the fan spins freely.

(remember on a Cinq it can start up even when the ignition is off)

 

[AJ 96]

it's a Seicento 2001 i will check later on, kt working last weekend but now its not
i was thinking maybe the fan could be seized or a problem with the thermostat

 

[David C]

Thermostats in general stick open when they fail, resulting in running cold.
Hot hoses also shows the stat isn't stuck shut.
A working heater shows the pump is working. (and you can use the heater to bring the temperature down)

The fan shouldn't be needed when you are moving anyway, but obviously is when stationary.

So, check the fan, but also check the rad itself too, if the fins are falling out the cooling ability will be dramatically reduced.

 

[AJ 96]

fan spins freely but before i checked anything else it started to rain so i will check later but where is the fan switch on a Seicento ?

 

[David C]

CF3 (which your 2001 should be) will have the fan controlled by the ECU, no "fan switch".
(that may apply to all Sei, not 100% sure)
If there is a "fan switch" it will be on the end of the rad.
(the end you can see!)

 

[fingers99]

2001 will almost certainly be an MPI car. See here.

If so there is no fan switch as such. The fan is switched by the ECU. The fan fuse is behind the battery -- two maxifuses there, one for power steering, the other for the fan. Check both: it's not uncommon for people to put the cover on back to front.

Again, assuming MPI, the easy way to test the circuit is to unplug the connector from the green coded sensor (the engine temperature sensor) on the inlet manifold next to the thermostat. Turn the ignition on and the fan should come on within a minute.

If it doesn't, pull the connector nearest to the fan motor and apply 12v directly to the fan (+ and -). Get back with the results.

I have seen stuck shut thermostats on Mk1 Puntos, and the result is rapid overheating with the fan not coming on -- no hot water gets to the fan switch. But I can't, because the ECU triggers the MPI on a signal from the engine temp sensor which is on the head before the stat, see that happening in quite the same way on an MPI car.

 

[cc1]

This is a good deal if needed..
http://www.ebay.co.uk/itm/FIAT-SEICENTO-Van-187-Radiator-Fan-BOLK-BOL-C021111-/271272267565?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Car+Make%3AFiat%7CModel%3ASeicento&hash=item3f29164f2d

 

[fingers99]

This is a good deal if needed..

Yes, that's incredibly cheap. Good spot!

 

[AJ 96]

got it fixed not sure what was wrong with it, just put more coolant in because it was just below minimum and bled the system

thanks Alex

 

[fingers99]

Keep a daily eye on the coolant level. Could "just" be a leak, could be something more significant.

 

[s and b]

maybe it lost its coolant because the fan didnt work as it was left with the engine running as you do the mot for things like emissions tests and exhaust leaks once up on the ramp
you really need to do a little more digging because water levels dont drop for no reason