Mk2 Focus 1.8 Duratec He - Coolant Temp Problem

[diddles]

Hi, I've recently purchased a 07 plate Focus with 49,000 on the clock. Ive noticed a problem with my temperature gauge, After just a minute or two with the engine running the coolant temperature gauge goes very quickly straight to the middle.The coolant temp reading on my phone via Torque app shows its only 40'c, and stays at about 71'c when driving.

Does this sound like a coolant temp sensor problem, or thermostat?

Thanks for the help!

Just checked the engine temperature in "test mode" in the instrument cluster and it read 106'c.

Edited May 21, 2014 by diddles

[artscot79]

Head temp in test mode which is 40 degrees higher than coolant so coolant temp was 66 the gauge is only a guide

[diddles]

Thanks for that. Could it be the coolant temp sensor then that's causing gauge to go straight to the middle after about a 1 minute after switching the engine on from cold?

[artscot79]

it may be normal as said once the engine gets to a certain temp the gauge can read warm ie in the middle even though it isnt as long as it doesnt shoot straight to the middle on starting isnt in the red and theres no running issues ide leave it alone

[mjt]

The gauge doesn't work directly from the temperature sensor(s), it's all handled by the ECU. As such, as Arthur says, it's only a guide and frankly not much more use than a simple warning light.

[diddles]

Thanks for the info but i think something is defiantly not right. I was monitoring the engine temp in the test mode on the cluster and while driving with light throttle it stayed at 111'c then i put my foot down and it jumps to 117'c then i let the throttle off again and it drops back to 111'c.

This cant be right, And the needle on the gauge goes from right at the bottom to dead centre within seconds and not gradually as the temperature increases.

I thought optimum operating temp would be 90'c, which means it should read 130'c on the cluster in test mode, if it does show 40'c over. So this must mean my car isnt even getting up to temperature as it never reads higher than 118'c.

Where is the coolant temperature sensor located so i can inspect and wiring of replace it?

I hope you can understand how I am explaining this. Thanks!

[artscot79]

111 is the head temp which will go up and down depending on many factors as you put the foot down more fuel is injected creating a bigger and hotter bang so the temp will go up due to this bigger hotter explosion in the engine as you ease off it will be less hot and so the temp will go down the test you are using will give you the heads temperature not the engine temp which is calculated by the ecu by taking the head temp and coolant temp together and working it out

90 degrees is not the optimum temp most cars run at over 100 degrees now for increased fuel efficiency as i said the gauge shows 90 but that is just a guide the coolant temp is what is shown on the gauge not engine temp and that wont always sit at 90 it can open it 90-96 degrees the gauge may say 90 when the temp is actually 60 degrees because its in that window where the ecu says the cars warmed up

if the gauge is instantly hitting the centre then its either the coolant sensor or the head temp sensor the coolant sensor is located on the thermostat housing on the right side of the engine

i will say sometimes you may open a can of worms by touching it if replacement doesnt fix what you see as an issue then youll be replacing bits forever

[diddles]

Thanks for the detailed reply. It just that the coolant temp on the torque app only reads a maximum of 79c and jumps instantly between 65 and 75c. Unless torque app can't read the temperature correctlly. I have no running problem so I think I'll leave it alone. Thanks for the replys just trying to get my head around the workings of this engine.

[salsheikh]

Martin

I've got the same issues as you with regards to the Torque app and even put a message on the torque forum but didnt get no responses so have left it as the car runs well.

[diddles]

That a good I suppose, it might just be a software issue between the app and ecu. The temp sensor is only £11 from Ford's so might stick one in at some point just to try it.

[jeebowhite]

Basically, the coolant is as it states on the tin, that is the fluid running around the engine passing through the thermostat and going to the expansion tank. The fluid is never going to be as hot as the engine, as its only taking the heatsoak, so you definately expect a difference. However, if your needle is jumping around between cold, hot and normal then you are best looking at the expansion tank cap. If there is a slight split or crack, this can cause erratic readings.

As the guys say, the dashboard is merely a rough guide, Torque is asking the ECU directly which gives the reading exactly as it sees it, however, the signal it sends to the dashboard will vary, much like the speedo is slower than your actually travelling, it sends a higher current to the wire to reflect the estimated reading. If it gets warmer, it sends more voltage, but its not regulated in the sense of "I have gone up one degree, so send an extra 1 amp / ohm" (purely an example) it says "I have gone up 5 degrees, so send an extra amp / ohm" this simple change of the voltage can be as much as a few mm's of movement in the guage, which doesnt accurately reflect the behaviour.

Now the other thing to bear in mind is that Torque is a universal app, it can be used on almost any OBD2 car and give you a certain level of detail. Now, Ford would say (as an example) for every 0.01 amps, the temperate is 1 degree - so their software would accurately report that 1 amp is 100 degrees at the engine, whereas Torque is universal and so will have a figure such as 0.075 amps to 1 degree, so when the temperature is 100 degrees at the engine, it calculates 75 degrees. If the OBD adapter your using supports all the Ford Protocols (highly unlikely) it can then pull back much more accurate information as it can query the ECU for the actual figures that its reading from the sensors and then convert that accurately to Torque.

Either way, the best thing to bear in mind is that if its not exceeding half way, its doing its job right, if its going up and down, then its not and there is a small fault. I would say for more accurate information, refer to Torque, universally its a good program and when compared with figures offered by the likes of the F Super, it is relatively accurate and is a good resource to see slightly more detail, but its not perfect and will not give you down to the fraction the perfect reading :)

[diddles]

Wow. Thanks for the informative post, it was very helpful! The gauge it self goes to the middle and stays there, so the gauge isn't an issue, it's just the funny readings from the torque app that was throwing me off a bit. I think I won't look into it any fuhther for now as it looks like it might be nothing wrong.

Just the temp gauge has acted like none of the other cars I have owned.

[jeebowhite]

If it shoots straight from 0 to the middle with no time after the key is turned, then there might be a stuck thermostat causing some confusion, however if it warms up quick and goes and stays to middle then its not a problem really :)

[JW1982]

If it shoots straight from 0 to the middle with no time after the key is turned, then there might be a stuck thermostat causing some confusion, however if it warms up quick and goes and stays to middle then its not a problem really :)

The temperature gauge shows a value which is completely calculated by the PCM. this is not a realtime value measured by the temperature sensor.

The needle going to the middle within 30 seconds has nothing to do with the thermostat. At that time the engine is still cold. Some of the MK2 and most of the MK2.5 instrument clusters do have this "problem". This is caused by a known software bug of the instrument cluster. Ford never solved this software bug.

For the MK2.5 instrument cluster there is custom firmware version available which improves the temperature readings of the temperature gauge. This firmware is included with the ELMconfig software.

[diddles]

I'm still having problems with my coolant temperature. The temperature seems to stay around 77℃ when driving which I think is to low. When stationary I'm able to get the temperature to 100℃ then the thermostat opens and the temperature begins to drop. But as soon as I start to drive again it stops to around 77℃.

Does this sound like a dodgy thermostat or could it be a sensor?

Also where is the cylinder head temp sensor located?

Thanks.

[artscot79]

you dont have a problem with the sensor mate as we keep saying the temperature will always vary think of it like this you get 100 degrees at idle not moving the coolant is now flowing through the radiator you move off and start driving the cold air going through the radiator cools the coolant down if the coolant is overcooling then as per normal the thermostat shuts to circulate it round the block only and keep the coolant temp up this is all going on constantly open close open close the cars not overcooling and its not running hot so from experience i say youre better leaving it alone

[fourspeed]

hi,

i just read this post and recently i have the same problem. At the first my test mode at lcd cluster reads Head temp at 112C. I've change the Engine Coolant Temp sensor and still the same. I check with OBDII and it says the engine temp is 78C when the fan kicks(that's 40C below the test mode head temp), that's too cool for duratec engine which should be 90 something celcius. My mechanic told me to change the ECT sensor which i already did and not solve the problem. So i try to change the thermostat with the housing because they're built as package. And now the test mode reads 135C which is around 95C on the OBDII. Maybe you should check your thermostat. hope it helps.

[Goodkat]

My needle goes to the middle within a couple of minutes from starting from cold, then sits there happily. I have never considered this to be a problem.

Sent from my Gen 1 WAP phone

[diddles]

Hi, thanks for the reply. I too changed the coolant temp sensor and it had no effect. How was the thermostat to change?

[fourspeed]

Hi, thanks for the reply. I too changed the coolant temp sensor and it had no effect. How was the thermostat to

change?

I am happy with thermostat change. The engine is running smoother, pinking is gone and i think the Fuel consumption is better (i will post the detail of fuel consump later). And i think the coolant temp sensor is just reading the temp not tell the fan to kicks, so it is the thermostat job to do that. i assume the old thermostat's spring is weak or something that causing the fan kicks too early before optimum temp achieved.

Sent from my iPhone using Ford OC

[diddles]

Did you change the thermostat yourself, if so was it easy to do or was it manifold off?

[fourspeed]

Yes i've change it by myself. You have to remove the passenger side's headlight to reach the stat, it located just beside the intake with 2 hoses attached. i open the clamps with pliers then pull the water hose with flat screwdriver. Remember you have to put new half gallon radiator coolant since it will be wasted by the time the hoses removed.

Sent from my iPhone using Ford OC

[artscot79]

Mine shows 135 in test mode as said that doesnt stop the coolant temp display varying the temp as i said its the coolant not head temp and coolant never sits at a solid temp ive had mine checked over and all is as it should be there's only an issue if like youreself the fans kicking in too early the dash readout gives the info

[diddles]

What does your coolant temp read on the cluster when driving normally?

[artscot79]

Reads just below middle as i said it will when the coolant is bypassed round the block once the thermostat opens and the coolant starts going through the rad it will drop as the coolants now cooler if its too cool the thermostat closes again hence the new focus and the active grill to prevent this from happening