My 2014 fiesta was running normally then started running cold when driving. I have changed the thermostat and housing and the problem persists. I have checked the thermostat in a pan of boiling water and it opens correctly however when installed in the vehicle the water seems to run past it allowing the hot water into the radiator. I have tried both the old thermostat / sensor and new thermostat sensor in different combinations but still the car runs on only 1 bar on the temp gauge. It will get up to running temp when stood still however as soon as you get moving it cools right down to 1 or zero bars on the temp gauge.

Has anyone encountered this issue before or have any ideas as to what the issue is as I am now at a loss. I can solve it by sticking cardboard across the radiator but would like to know what is happening and solve it properly not just a quick fix.

Hello,

I had exactly the same problem as you but fitting a new thermostat fixed it for me although mine still takes a while to get to temperature but it does stay there now.

Did you change both thermostats? There are 2 on the 1l eco.

There is another hidden away near the alternator. Not easy to get to. The circled green one.

Hi thank you I dint know there were 2 thermostats so I will look at changing the second one too to see if that solves the problem.

I have replaced the second thermostat. That is a really difficult piece to get to though. You have to drop the air conditioning compressor down out the way, remove the alternator and then its hidden at the top of the engine block behind where the alternator was. Its definitely a full day job. So far though it looks like this has solved the problem and the engine heats up normally. Just need to test it over the next few days on longer runs.

Thank you for your reply I had no idea these engines had 2 thermostats.

No problem. Glad it seems to have fixed your problem. It took me most of the day to get to that one as well.