Hi All,

I am been having a problem with my car for quite a few months now, had a mechanic look into it but still no luck just wanted to get some further advice and see if anyone has had or knows what the problem might be.

Car: Ford Focus, 2001 - Automatic, 1600 engine.

Issue:

The temperature gauge after approx 10 minutes of running is going right up to the highest point suggesting the car is completely overheating, however it is not. If I stop at traffic lights for a few minutes, it will drop back down again to the middle. If I go uphill for any length of time it will shoot up to the top almost immediately and stay there and at this the point the car engine management will come on. Also, a flashing exclamation light will appear on the dashboard.

This happens every single time I drive the car, I am only doing short journeys at the moment (around 30 mins or so) - not been on the motorway. To be clear, the car is definitely not overheating it is just the system showing that on the dashboard.

My concern is if I do take it for a long drive I could have a breakdown etc..

What has been done to date:

- New radiator fitted
- New temperature sensor fitted
- Pipes checked
- Dashboard reset

I have had a highly qualified mechanic look into the car on multiple occasion, he is old school and has said he believes it may be more of a computer issue than a mechanical issue as all the tests so far have been unable to replicate the issue off-road.

The main reason for asking is, I am not confident enough to take it to a garage without some kind of idea what the issue is, I don't want to spend more money on investigation work. If someone can pin-point the cause I can take that back to the mechanic or another garage.

Would appreciate any help/suggestions.

Many thanks,

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water pump failing 

 

1 hour ago, keefymc said:

What has been done to date:

- New radiator fitted
- New temperature sensor fitted
- Pipes checked
- Dashboard reset

Thermostat sticking?

If it is an ECU problem, then it will be hard to rectify. A new ECU fitted and programmed by a Ford dealer would be much more than the commercial value of the car, and a 2nd hand ECU is not easy to fit and programme on a DIY basis. Shame, as a Mk1 Focus is becoming a bit of a near classic car now.

I would fit a separate temperature sensor to the engine, just a thermistor strapped to a rubber hose near the CH (cylinder head) works quite well, but is quite a lot of work, with wiring and some sort of display device. I have extra temp. sensors on the AC, CH, radiator feed, and air intake on my car, going to a custom built display, but then I do like to see what is going on under the bonnet! The Ford dash temperature gauge is almost useless, really.

Also check that the radiator fan is going at top speed if you stop with the temp. gauge at the top of its range. I am pretty sure that there is only one temperature sensor, used for fan control, gauge and warnings, so if the sensor is wrong, all three should get the same high temperature status. (Certainly the case on the Mk2 Focus.)

Also I would get another temperature sensor, and compare the resistance readings on its pins at various temperatures with the one you now have. A faulty replacement is not impossible.

Also I would try to check the wiring connections from the sensor to the ECU. Not easy without the circuit diagram, but better than scrapping the car. I have the Mk2 circuit diagram (it is on this site), and the Mk1 is similar in many areas, but no guarantee.