Hi folks,

All sorted. It was a stuck thermostat. Replaced it after a learning curve without taking the alternator and belts off, etc. This walkthrough might help someone else, it seemed to work ok for me.

You need two people as you are trying to find three bolts in particular totally blind and they are b*****s to locate.

1. Drain coolant

2. Completely remove bottom radiator hose from rad and thermostat housing

3. Remove smaller hose from thermo housing and tuck out of the way

4. Undo lead to alternator (10mm) and tuck out of way.

5. Now, with 8mm extended bit, undo the four bolts that hold the housing on. You can see the top left one if you look very carefully. The bottom left one is tucked underneath the larger inlet pipe and is an absolute sod to get to and completely invisible. The bottom and top right bolts are visible from below and an assistant can guide the 8mm bit onto them quite easily.

6. They are only nipped up, so quite easy to undo.

7. Remove housing and thermostat

8. Remove thermostat seal ring and throw it (replacement thermo comes with a new one).

9. Clean surface of housing and engine block as best you can being careful not to damage the rubber ring in the housing (can be removed and cleaned, I couldn't find a replacement without buying a new housing so as mine wasn't cracked or damaged I used the rubber seal again).

10. Replace thermostat making sure that you insert it into the tiny split inside the seal ring so that it sits in place seceurely and that the vent hole is at 12 o'clock).

11. Put the large hose on the housing BEFORE you put the housing back in place (the clamp is a vicious brute and without the right tools is impossible to put on afterwards (or use a jubilee clip if you want to risk that).

12. Slide the housing back into place and put on the smaller hose BEFORE bolting up for the same reason as above.

13. Replace the four bolts with the aid of your lookout and do NOT overtighten.

14. Replace bottom hose to the radiator.

15. Fill with coolant and go.

I was quoted over £300 for this job because a garage will remove half the engine compartment to get to the thermostat housing easily. They also have to replace the belts as they are single-use belts. It's four hours labour plus parts.

I did it for £7 plus anti-freeze (you can keep the old stuff if fresh and re-use it) but it took me two goes as the first time I tried on my own and got it wrong. Doing it the way I describe above with two people took about 90 minutes, and avoids more complicated mechanical work.

Hope this helps someone.

Edited by Bottom Feeder on 06/08/2015 at 22:33

Remove the top hose and fill it slowly from here.

If it's not HG,it's the pump.I echo Skidpan;put the heater on a Ford on full blast and run engine at 4000 rpm for five minutes.

Back to square one!

EXACTLY the same symptoms, and I am now convinced that this is an air lock in the coolant system.

Wishful thinking?

Sorry to say that 'water bubbling out of the header tank so violently' would almost certainly be caused by a failed head gasket. How old? How many miles?

This is an interesting thread, please keep us posted.

If you havent had the check for combustion gases done, you would be advised to now as its possible you may have a cracked head, this would give the various scenarios you are talking about as it depends where the crack is as to when the gas escape occurs

I dont recall these having bleeding problems but others may have different experiences with this engine, the other possible as mentioned i think is failed water pump impeller or partially failed, nothing is impossible with mechanics

It won't account for two litres so I think I'll pass on this one.

What WILL account for two litres other than an air lock???

The garage won't check for gases due to the explosive nature of the fault - there seems to be no way of telling when it will blow!

Did you think that up or did the garage actually say that, untill items are eliminated you are going around in circles, so I suggest finding a garage that knows what they are talking about/doing and get it checked

If there is no gases present then look elswhere,

The garage won't check for gases due to the explosive nature of the fault - there seems to be no way of telling when it will blow!

Change your garage.

Any update on this, please?

, but the bottom hose is hot sometimes, cold sometimes - there is just no pattern to it.

Could the pump impellor be loose and intermittently losing adhesion with the drive shaft on this model? I seem to remember reading about this diagnosis somewhere. If it isn't this then it must be a failed HG or, more rarely, a crack somewhere in the head or block communicating with the water channels.

1 Possible I forgot about that happened many years ago on a few Fiestas, same as yours and it was caused by a leaking hose connection

ie the hose had cracked internally on the joint below jubilee clip and as engine cooled off it pulled in air, it never once leaked water but sucked in air,it took ages to find the problem but it was eventually just a thought anyway

Sorry,

I've not been well - just getting back into the saddle.

I thought I'd make a few more things up as I go along - why is there always a troll under the bridge just when you don't need one?

I'll let you know how I get on and thanks to the genuine guys that are interested in helping; those that prefer to take cheap shots or just extract the urine can go and do one.