Hi All

I am really amazed with the info I get from this forum and everybody seems to be very nice as per what i read from the threads..so I decided to join..I am also a new owner of a fiat seicento sporting 1.1..bought it about two weeks ago..its my first ever fiat..and I love it! problem is just about three days ago the temperature warning light suddenly came on it's dash..changed the thermostat, coolant temperature sensor and radiator fan switch but the warning light still turns on when hot..i also have bleed the radiator following the guide i found here but still the same..there is no oil in coolant, does not leak or go low on coolant either..it starts fine and seems to be ok..fan does kick in as well..any suggestions what i may still need to check or replace? water pump is new also and coolant in expansion tank does swirl..i have not taken the sei on the road since i had this trouble just in case..

Puzzle.

It has been known for cheap and nasty thermostats to not open. This will cause very rapid overheating. Only use "real" ones.

Alternatively, and assuming SPI, folk have been known to fit the coolant temp sensor from a Cinq with a temperature guage. With odd results.

The Sei one is just a thermo-switch, the Cinq Sporting one a variable resistor.

Use a competent spares provider. Fluffy at eurocarcare.net or Shop4Parts recommended (and discounts for donating members).

Thanks for the reply fingers..it is really kinda strange..I have also bought a new expansion tank cap and waiting for delivery..also this afternoon I noticed the ? ecu temperature switch (sensor at back of engine right side facing car just under coil) having a dry blue powdery like substance which somewhat leaked at the joining between the bolt and electrical connector.. Could this mean that the sensor is now kaput hence ecu keeps on reading that my coolant is boiling although I only ran the car about 5-10 mins.. I have as well ordered one so hopefully it will be sorted out..I really like driving the Sei.. Handles better than what I expected.. Anyway with regards to the thermostat how do i check it if it's working ok without removing it from car? I bought one from eurocarparts

I'd treat anything other than oil and filters from eurocarparts with extreme suspicion.

Very difficult to check the stat and, if the fan actually comes on, I'd suspect it's working -- at least, after a fashion.

You could see what kind of sensor you have by removing it, seeing if you get a variable resistance (ohmeter setting on a multimeter) when popping it in a pan of water and bringing it to the boil or an on/off response.

But, what happens when you remove the electrical connector -- does the light go off or stay on?

The blue stuff is probably the result of nothing more than verdegris on the body of the sensor.

I have not tried taking the connector off from the ecu coolant temperature sensor (blue plastic connections) but I did try to disconnect the connector from the coolant sensor (one by the block of engine timing belt side) and the dash temp light turned off but I have replaced that sensor already and it is still on..
Am i right in thinking that..well supposed that all sensors are working; that the dash temp light would only turn on if the coolant temp rises to way beyond hot? But in my case i am hundred percent sure it is not even boiling because I can still dip my fingers in the expansion tank and I can still touch the side of the block when temp light turns on in the first 5 mins of warming up engine...

certainly sounds like its not actually overheating, 5 mins isn't even long enough for it to be at operating temperature even if the stat was stuck shut...

Sounds like the signal wire is shorting somewhere so the light comes on but you'd kinda expect it to just come on with the ignition if that were the case... I'm curious, if you turn ignition on and don't start the car and leave it for a few mins whether the light would come on, as you changed the temp sensor already its doubtful its that and this is a really simple circuit... When the light comes on does it come on dimly and get brighter?? That would be the wrong sensor if so, cinqs have sensor in same place on the rear of the head but its a variable type as they have an actual temp gauge, the sei one is an on/off type and will result in the light coming on and getting brighter and brighter as the car warms up.

Hi blu73..actually you are right..the temperature dash light does start from dim then goes brighter as the engine warms up.. I have not tried leaving the car on "ON" to see if it would turn on by itself.. Any suggestions regarding the circuitry of the dash light? I am not very good at electricals really so any help is greatly appreciated.. I was thinking if there is any way to reset the ecu maybe?..please help..really dying to drive the Sei..

ah, well if it comes on and then gets brighter its safe to say you just have the wrong sensor in it and probably the one before as well and that there isn't actually any problem here other than that.. This is pretty common mistake on the sei now they are getting old enough to have had stuff like this swapped. Ring up Big Mick at EuroCarCare (http://www.eurocarcare.net/) and he will sort you out with the right sensor.

Thank you very much blu73..really appreciate the input..I will ring big mick..anyway..just to add and maybe it will make some sense..previously the alternator was also overcharging and the battery light was on.. i tried tapping the alternator with a hammer as maybe the brushes are stuck then the battery light turned off so went on driving the Sei but only briefly after which battery light came on again but this time together with the temp light..I have changed the alternator but the grief of the temp light is what I am trying to sort out..

was stupid they didn't fit a proper temperature gauge in the sei.. not expensive task to fit one though, and easy job too if you would like a real gauge, there is a guide in the guides section

Get this sorted and then see if you have any joy with the alternator light.. I have a known working alternator for sale in the classifieds if you need one when it comes to that.

update..alternator now all done so no more battery warning light but the temp light still turns on after just idling for 5 mins.. I bought a different sensor from shop4parts the one with a red plastic covering the single pin hoping that it is the correct one but it still did the same thing..it just slowly illuminated from dim to bright..bled the cooling system again..radiator not blocked and looks ok, never losses coolant, never boils coolant no matter how I run engine, no oil in coolant, no mayo under oil cap or dip stick, engine runs ok, idles ok, radiator fan kicks in nicely, all sensors now replaced (radiator fan, ecu coolant temp and coolant temp by spark plug number 1), tried revving it steady to about 2000 rpm and top and bottom radiator hose does not go hard..

I also have enquired from eurocarcare.net for the correct sensor and now waiting for their reply.. anything else i can do?..maybe i will just stick a water temp gauge so i can monitor the coolant temp.. but it is really annoying that I can not resolve why the temp light turns on when the engine never exhibits any sign of overheating due to head gasket, radiator blockage, fan problems..it just makes me scared to use it..

You've still got the wrong sensor...
Happened to me, temp light slowly brightening up even when car was not
over heating...
You need the switch on at a certain temperature sensor..


Phil

Hi Phil..any info where to buy a proper one?

yep still just got a temperature sender rather than temp light switch... If ring Mick and tell him you need the switch type for a seicento he will sort you out i am sure.

But i believe its part no.7588920 for the switch type.

mc858 said:

Hi Phil..any info where to buy a proper one?

Click to expand...

Got mine from Mick IIRC



Phil

Big Mick (aka Fluffy the Impaler) or little Mick at eurocarcare.net in sunny Derby.

Hi Guys..thanks again to all forum members specially those helping me out..you guys are just amazing..anyways big mick suggests changing the ecu coolant sensor; the one with a blue connector back of engine right side; which I have done already and still does the same..trawling the Internet I found a seicento coolant sensor with a 115 deg celcius temperature switch on/trigger..any thoughts?..

switch/trigger would suggest that it is an ON/OFF type..

Just realised I didn't get mine from Mick..

It was from here...
[ame]http://www.amazon.co.uk/gp/product/B00HAH8QT8?psc=1&redirect=true&ref_=oh_aui_detailpage_o06_s00[/ame]


Phil

A great big thank you to all who helped me!!!..just to update..it was the wrong sensor indeed! i have also installed an aftermarket water temp gauge for good measure! The Sei is working fine now and my son will be learning from it soon..