Hi, 

I have recently purchased a 2016 1.5L TDCI Focus estate. My coolant reservoir after every trip is always low (empty).
However when I open the reservoir cap it is still pressurised and some coolant comes back into the reservoir. I have just done an oil change and there is no signs of a head gasket leak.
It also comes up to temperature well and then stays consistent no matter how long the drive is.
I have tried running the car without the cap on with the heating on full to see if it was an airlock causing it, but despite a lot of bubbles coming up, it is still losing coolant. It recently had the timing belt done, so I was thinking maybe it could be something to do with the water pump? I can't see any visible leaks either. Last night I filled the reservoir up and left the cap off to see if it would leak onto the drive, but it is still full. 

 

Any suggestions on diagnosing this would be much apricated, I'd rather not have to take it to a ford garage and pay £167 for the diagnostic test.

 

Cheers

If the water pump has been off then it will be air.

Run it with the cap off until the thermostat opens (which will take forever on a diesel) or ,VERY CAREFULLY, remove the cap after a run, so you know it's hot and top up while running with the thermostat open.

Then switch off and leave the cap off, preferably over night, then top up again when cold and refit cap.

If it carries on doing it after that then you have a problem somewhere else.

Obviously check for leaks, especially under the expansion tank

Thank you Dave!

I did trying running it with the cap off and heaters on to get the thermostat to open. But admittedly I've only had petrols before, so I didn't run it for as long as I should have so the thermostat probably didn't open. 

I have just googled the capacity of the coolant system, which is around 7.3L. I fill the expansion tank up every time which is around 1.2L. I imagine I've put well over 7.3L in, so leaning towards a leak. 

I'll try the thermostat again, and hopefully it works or atleast helps pin point the leak.

 

Cheers 🙂

Don't run it with the heaters on, that'll take more heat out than the engine puts in.  The matrix on these is a constant flow anyway.  I agree with Dave on taking it for a short run first rather than idling it on the driveway.

I'm having same issue. Please have you fixed yours and what was the cause?

 

1 hour ago, Akins said:

I'm having same issue. Please have you fixed yours and what was the cause?

This the WRONG forum to be asking questions.

Please repost your question in the ECOSPORT forum not in the GUIDES forum 🙁