Radiator fan never starting ('96 Punto)

oq4v3ht0u76kf2

Hi all,

Having a bit of a problem with a 1996 Punto where the heater is only blowing cold air, mentioned it here earlier this week but further investigation has shown me that the radiator fan under the bonnet is never starting.

I've bled the cooling system and gotten rid of any air, I've filled it up fully with coolant (and a bit of Radweld+ to be sure), and the engine is still heating up. If I leave it run with the bonnet open for it hits the mid-way mark on the temperature gauge after about 10 minutes and is into the red after 25 or so.

However, the radiator fan doesn't start. Ever. I've tested it by applying 12V directly to the motor and it works fine and spins perfectly so it seems that whatever mechanism in in the car tells the radiator fan to come on isn't working. It's reading the right (HOT!) temperature in the dash but still the fan doesn't kick in.

Any ideas guys?

MarkoC

Renata Rotten Gladiator wrote: »

Hi all,

Having a bit of a problem with a 1996 Punto where the heater is only blowing cold air, mentioned it here earlier this week but further investigation has shown me that the radiator fan under the bonnet is never starting.

I've bled the cooling system and gotten rid of any air, I've filled it up fully with coolant (and a bit of Radweld+ to be sure), and the engine is still heating up. If I leave it run with the bonnet open for it hits the mid-way mark on the temperature gauge after about 10 minutes and is into the red after 25 or so.

However, the radiator fan doesn't start. Ever. I've tested it by applying 12V directly to the motor and it works fine and spins perfectly so it seems that whatever mechanism in in the car tells the radiator fan to come on isn't working. It's reading the right (HOT!) temperature in the dash but still the fan doesn't kick in.

Any ideas guys?

Coolant temp sensor gone 100%

oq4v3ht0u76kf2

Liking the confidence Marko! So is that an easy yoke to replace or am I looking at sending it in to a mechanic?

MarkoC

Renata Rotten Gladiator wrote: »

Liking the confidence Marko! So is that an easy yoke to replace or am I looking at sending it in to a mechanic?

Easy job, just follow the wires from yje fan and you get to the sensor, the rest is just a spanner job, you might need some more coolant as well to top up after replacing it.

oq4v3ht0u76kf2

Any idea what it looks like? I've gone looking just there but can't seem to find anything that looks like what I imagine!

MarkoC

Similar to that



Get your online quote from them

http://www.micksgarage.ie/autoparts.aspx?dept=361&ga=830&b=57&AssemblyID=102747&MakeID=35
They have pics as well when you get to the right product for your model.
You looking for the one with 3 pins

Avns1s

I would have thought it more likely to be the thermostat that's at fault. If its stuck, it won't allow the hot coolant to the sensor to activate the cooling fan. Secondly, with the cold weather, it would be unlikely that when driving the car, the cooling fan would come on at all. There would be plenty of cold air going through the rad even at very low road speeds.

BrianD3

So you have a hot engine, a non starting fan but a cold heater? If something (such as a blockage or bad water pump) is stopping flow of coolant around the system you could get those symptoms. Some parts of the system could be hot while others are cold. If your fan sensor is detecting a cold temperature then your fan will not come on even though other parts of the engine may be overheating.

I don't think its the thermostat as if you had a stuck closed thermostat and everything else was working your heater should still get hot.

When the car is overheating are the radiator and the hoses attached to it hot?

Edit: when the car is "overheating" is the engine block very hot to the touch. If it isn't then you could simply have a faulty temperature gauge

MarkoC

Avns1s wrote: »

I would have thought it more likely to be the thermostat that's at fault. If its stuck, it won't allow the hot coolant to the sensor to activate the cooling fan. Secondly, with the cold weather, it would be unlikely that when driving the car, the cooling fan would come on at all. There would be plenty of cold air going through the rad even at very low road speeds.

Easy to check, if the main radiator is hot its not the thermostat fault.

Avns1s

MarkoC wrote: »

Easy to check, if the main radiator is hot its not the thermostat fault.

If the thermostat is stuck closed, water won't be circulating to the rad! (or possibly to the heater)

MarkoC

Avns1s wrote: »

If the thermostat is stuck closed, water won't be circulating to the rad! (or possibly to the heater)

He said its cold in the cockpit ? If small circle is hot it should heat it as far as i know, that means the water should be on the main circle and temp gauge pointed at RED zone after 25 min what sounds ok so far... Theres no temp sensor on the small circle as far as i know ...
But in that case i dont understand why theres no warmth in the car ... Thermostat open all the time . ?

I might be wrong here of course ...