General Urgent Help Needed - Fan not coming on

[Tweedbean]

Hi fitted my new radiator in the heater matrix, bled the coolant system and the car was running fine. But on the way back from my test drive the overheating light came on. I pulled over, not losing water, then suddenly realised that during my 10 min drive, plus 10 mins of the car running before driving it, the fan had not come on once.

What are the possible problems that would cause this?

Checked the fuse in the dash for the fan, thats fine. Just found out theres a fuse under the bonnet, behind the battery, so gonna check this next.

Urgent as I need the car for work tomorrow.

Help would be well appreciated

 

[ATOMIC DOG]

is it overheating or have you got a faulty warning light sender?

you say you did'nt hear the fan while bleeding the cooling system or while driving,its unlikely the fan will come on while the car is on the move.i might be wrong but it sounds like you've not bled it out correctly and there is an air lock,i always wait until the fan comes in before i put the bleed screw in and the rad cap on,usually more than 10 mins.

is the fan motor siezed?

if it has a rad fan switch,bridge the electrical contacts if the fan comes on and your certain its bled out correctly the rad fan switch is u/s.but your fan might be ecu controlled which is more likely to be the water temp sender.

 

[Chrisst10]

You'll most likely find that the Fan thermo switch is knackered.

Best thing to do (to check if the fan itself works) is to locate the thermo switch. Its on the right hand side (standing infrom of the car) of the radiator. Its basically a green (i think) plastic connector that has 2 wires going into it and is bolted onto the side of the radiator.

Disconnect the cables and turn the ignition on. Now bridge the 2 wires (make a connection). If the fan turns on then the motor is fine and its likely that the thermo switch is at fault. If the fan doesnt come on (make sure you have definatly bridged the contacts properly) then its likely that the fan itself is knackered.

Really your car shouldnt rely on the fan to keep it cool so if its overheating its likely that something else is at fault. The fan is only needed when the car isnt moving. The fan should not operate when the car is moving. if it does then something else in the system is at fault.

 

[Tweedbean]

Just checked the big fuses under the bonnet and their fine

 

[Tweedbean]

gonna give it to a garage tomorrow so they can work out what the problem is, then I might attempt to fix it

 

[Chrisst10]

No offence but what was the point in posting this thread if your not even going to bother trying the suggestions people have made?

Takes all of about 2 minutes to check the fan switch and 95% of times the fan in a cento isnt working is down to a duff fan switch.

You obviously like throwing money away if your going to give the car to a garage to diagnose something that people on here have already diagnosed for you. Feel free to throw some my way next time your wallets getting a little heavy.

 

[Tweedbean]

Chrisst: Is it this bit under the horn, can I get to it if I jack it up, or do I need to take the bumper off.

Will try testing it but dont have the time as Ive just started a new job

 

[keithmercer]

It is the bit under the horn. It is best to get at it from the underside (made eaiser if you jack the car up.

 

[Chrisst10]

You can get to it from the top perfectly easily. Only time you might have to come up from underneigh is if you are replacing the switch. To test it, all you need to do is remove the cable which is a clip.

 

[Tweedbean]

Thanks for the advice, me and my dad are gonna have a look at it on sunday.
Hopefully the parts arent to costly, dont you just love owning a FIAT

 

[ycming]

You say the fan doesn't come on ?It has to reach a certain temperature before it comes on.

For a 899 it only comes on when it is at 90.

Just making sure

Ming

 

[Chrisst10]

Last time I bought a new fan switch, it was under a tenner from Fiat. A few years ago mind.

 

[Tweedbean]

Last time I bought a new fan switch, it was under a tenner from Fiat. A few years ago mind.

Just done the test you said, to bridge the cable and the fan came on, hopefully the fanswitch, is there any way of testing it or should I just buy a new one?

is it easy to fit?

 

[fingers99]

Just buy a new one. effectively, by bridging it, you've proved that the circuit works without the switch. Ergo the switch is faulty. QED.

 

[Tweedbean]

Yeah going to buy one tomorrow
Hopefully thats the last problem

 

[Tweedbean]

£11 from Fiat, got to go and pay for it later, as they have to order one in.

Flushed it out properly today as well.

 

[Tweedbean]

Nope not worked, fan still not coming on, have bridged the switch and the fan comes on so that works, fitted a new fan switch.

checked the top radiator pipe and its warm so thermostat is working.

Water gurgling out as steam from expansion tank lid. overheating light is not coming on.

been flushed three times.

any ideas?

 

[fingers99]

Bleed it carefully.

If that doesn't do it, either get someone to run a pressure test on the cooling system or a compression test.

 

[Tweedbean]

Yeah just gave it to a garage round the corner that have worked on the car before, they're trustworthy and not the sort to charge me for stuff that doesnt need doing. They are going to flush it properly and pressure test it.

 

[fingers99]

Get them to test the cap while they're at it. On t'other hand, they're so cheap it'd be worthwhile buying one.