Technical Intermittent Engine Light

Currently reading:
Technical Intermittent Engine Light

TheGrinchUK

New member
Joined
Dec 7, 2021
Messages
5
Location
Manchester
Hello Guys, Girls

I have an intermittent Engine Light on my 2003 Fiat Punto

I know the light has something to do with the Water Temperature Sensor as i have had RAC come out and plug in their diagnostics computer.

I have replaced the sensor with a brand new one to which the engine light went off however when driving to work today and getting stuck on the motorway for a couple of hours the EML came back on. When looking at the dash the temperature valve had completely dropped back to 0.

On my way home from work the EML light was still on and after approx. 15 miles the temperature valve started to work again but the light stayed on.

I have looked at the radiator fluids etc and they are normal although it looks like it has been filled with water as opposed to anti freeze

Do you have any potential ideas as to what else i could check to see where the problem is arising from?

Many Thanks
 

Mike1alike

Active member
Joined
Aug 3, 2017
Messages
427
Location
Timisoara
I think the air bleeding to the cooling system was not performed correctly so you have air pockets in the system. And when air gets around the temperature sensor, the temperature cannot be measured and gives you low readings.
You should put antifreeze in, do not let it run on just water, especially with the winter coming. Do the proper mix, antifreeze + water 1:1.
To bleed the system the best is to park with the front wheels on higher ground. Select the air inside the car to hot and start the engine. Open the air vent located top right on the radiator and the air vent located on the matrix that goes to the heater. When liquid is coming out through the vents you can stop the engine. Then take down the air vents and top up the antifreeze untill no air comes out, just liquid. I think the radiator will be the first with no air so then you can close up the air vent on the radiator. Next, continue to top up the antifreeze untill the heater is filled up and no air comes through its vent. Close up that vent as well and if the antifreeze level is above max, you can take out what's extra using a hose or something.
 
OP
OP
T

TheGrinchUK

New member
Joined
Dec 7, 2021
Messages
5
Location
Manchester
@Mike1alike

Thank you for your guidance, I emptied out all the liquid from radiator etc, Topped it all up with fresh and bleed the system from radiator and the heating matrix. Have not seen the warning light come back on since

Many Thanks
 

dumbledore

Active member
Joined
Jul 4, 2010
Messages
745
I had this problem. In my case the fault was the thermostat. In cold weather a faulty thermostat cause the temperature to vary a lot depending of driving causing the engine management to complain and through an error. A good thermostat should make the engine warm up quickly and then the engine temperature should stay constant independent of outside temperature and driving mode.
 
Top