Technical Low temp and engine light

[Mandabee]

Hi all!!

Looking for some advice and help really.

Driving my 53 plate 1.2 8v punto last night and all of a sudden my temp gauge dropped straight down and then the engine management light came on when I got in I heard the fan (havnt really noticed this before) anyway I get in it today it was the same but after about 10 - 15 mins of traveling the gauge as then raised to the first 1/4 but the light was still on......

(Thinking temp sensor and thermostat are the issues)
Any idea guys if I'm thinking correct?

 

[a1ant]

Hi,

Sounds like failed CTS (coolant temperature sensor) or a dodgy connection / wiring to it. Best way to confirm is to connect to diagnostics and read the fault code, and then test the CTS.

When the ECU receives no signal from the CTS (open circuit) it brings on the warning light and kicks in the fans as a safety precaution. The CTS is essentially a thermistor... its resistance varies depending on its temperature and the ECU reads this resistance and converts it into a temperature reading and adjusts fueling and activates deactivates the cooling fan(s) accordingly. Sometimes when thermistors fails, they can go open circuit between a certain temperature ie up to 40oC and then "somewhat" spring back to life when past say 40oC.

Alan

 

[s and b]

ive had this and it was caused as a1ant says
but it was because somehow it got an air pocket rather than water in front of the thermostat i think
a new thermostat cured it,i think the water boiled here to ether because the thermostat didnt open so next would be a head gasket job


i could be wrong but i would change thermostat pronto

 

[Mandabee]

Update --- I got in the car this afternoon/evening and the engine light had gone off and the temp gauge was slightly rising. I'll still be getting the temp sensor,thermostat etc done for my own price of mind!!

 

[Mandabee]

Thanks got your help guys!!

As anyone got a rough idea of the cost if I send it a garage?

 

[Ziggy122]

New Punto Stat is £15ish delivered
New temperature sensor is £30 ish delivered
You might as well be doing the coolant as well, it make perfect sense to!
So £15ish for 5L neat,

So in parts alone you looking £60
Todo a stat you need to drain coolant, and todo temp sensor, i'd be looking 2hr max labour

Assuming Labour is £30 to £60 ph, your looking at around £100 to £150

Tbh both are reasonably easy DIY with decent sockets and a roof over your head, it horrible working in windy wet weather

ziggy

 

[MikeSalt]

Tbh both are reasonably easy DIY with decent sockets and a roof over your head, it horrible working in windy wet weather

Tell me about it! Just spent two hours lying in a puddle replacing a lambda sensor. The sensor itself came out easy, it was threading the cables through the engine bay that took the time.

Mandabee, I've recently done a thermostat swap, so please don't hesitate to ask for any pointers

 

[Ziggy122]

Tell me about it! Just spent two hours lying in a puddle replacing a lambda sensor. The sensor itself came out easy, it was threading the cables through the engine bay that took the time.

Mandabee, I've recently done a thermostat swap, so please don't hesitate to ask for any pointers

Coil pack out the way done help
oh and some decent grit paper to clean engine face up with

Ziggy

 

[Mandabee]

Thankyou for your help guys!!

I've got my fellas brother on the case today he is replacing them as we speak ?

I did ring a garage yesterday and they said approx £100 ?