mk 4 fiesta encore temperature guage

[j77drs]

i have a 1997 fiesta encore - 1.3 endura e engine
today the temp guage went right up into the red, even though the car was not fully warmed up, i left it tunning and the fan does cut in,
i used the car again and the guage is now showing slightly hotter than usual
any ideas why this would have done this ?
im assuming its not the CTS as the fan has cut in

 

[Mursal]

It may well be the CTS as at that age some had 2 one for the gauge and one for the engine management. Some even had another in the radiator especially for the fan.
As long as the engine isn't overheating you are OK.

The fuel gauge uses the same supply as the temp gauge, so if its still "stable" check the sensor, probably a single wire one in the head. If you touch the wire on the engine with the ignition switched on, the gauge needle should hit the roof? Just make sure its the correct wire, before you go earthing it.

http://www.ebay.co.uk/sch/i.html?_sacat=0&_from=R40&_nkw=97+fiesta+coolant+sensor&rt=nc

Single wire sensor third from the top


Hope this helps

 

[j77drs]

thanks for your reply

the guage sensor is in a pipe behind the inlet i believe, i have checked and there is one there with 2 wires

there is no bubbling in the expansion tank and the fan cut in so im assuming its not overheating ?

 

[Burnerman]

You are correct, the temperature gauge sensor is located within a rubber hose at the back of the engine.
If you suspect there are other issues, consider replacing the thermostat, under the domed housing, engine offside, top.
John

 

[j77drs]

i dont think there are other issues as the heater is fine, likewise the fan is kicking in ok

the onle issue is that the guage is so close to the red, then on another journey it went back to normal

are these a common fault ?

i dont think the car is overheating as there are no signs of this, ie bubbling water etc and the fan is kicking in

 

[j77drs]

also i have a mini diognostic and the car is not showing any fault codes

 

[Burnerman]

Just keep an eye on things really.....if the rad fan switch isn't near the top of the radiator, then the fan is switched on by other means.
When the temperature gauge is reading normal or above, the entire radiator surface should be hot, together with the top and bottom hoses.
If the fan is on, but the rad is cool, then there could be a circulation problem.
Engine fault codes won't show up for this issue.
John

 

[j77drs]

yes top and bottom hoses are hot

this is what leads me to a faulty guage senderin the hose behind the inlet manifold

 

[Burnerman]

It seems like yourself and Mursal have the correct diagnosis....I'd replace the sender as soon as you can though.
Overheating will give a popped head gasket in time, and thats a real bore.
John

 

[j77drs]

if its just a fauly sender then why would it be overheating ?

i see no signs of this

what should i look out for to see if this is infact overheating ?

 

[Mursal]

Go to your parts supplier (main dealer or otherwise) ask for a coolant temperature sensor for your car. If they are good they will tell you all coolant temp sensors listed. If your can has a single wire sensor fitted, change it.
If on the other hand your car only has a two wire sensor fitted, change it.

Do not keep driving with the temperature gauge inaccurate, because if it is not the sensor that's at fault , you will do expensive damage.

This in our experience is the easiest way to resolve this problem.

 

[j77drs]

hi

im now not sure it is the sensor, i drove the car today and the guage was reading midway ( a little hotter than usual ) iot sat at this all the time

i checked the hoses and the top hose is hot but the bottom hose is only luke warm, likewise with teh rad this is not hot at the bottom

any ideas ?

 

[Mursal]

Convection current in the coolant helped by the water pump makes the hot water enter the top of the radiator. It cools in the radiator falling as it does so. Therefore the bottom will never be as hot as the top.

Like I said, we have found the method outlined in the previous post the best to rule out the sensor. If you think the thermostat may have stuck closed and is now working OK, just keep an eye on it, or take it out. You will have no interior heat, while under test without the stat.

 

[j77drs]

i just checked again to make sure the fan was going to cut in and there was no airlock,

i left the car running ( tick over ) and took the expansion cap off,

the fan did not cut in and the expansion tank boiled over

any help appreciated

heater is working fine inside the car if this means anything ?

 

[Mursal]

I don't know, it may have just boiled over due to loss off pressure when you took the cap off, or its overheating. Let the engine cool down fully and top the coolant up.

Run stationary with the cap on until the fan cuts in or it blows the coolant out, it might take a while. If the fan cuts in with no violent loss of coolant, happy days.
Or drive it checking the coolant as you go. Have coolant (water) with you until you get to the bottom of the problem. Remember cold coolant into a hot engine means expensive repair bills, so let it cool down first.

If its not overheating, leave it alone until you get a sensor.