I've been noticing recently that the temperature gauge in my 2015 Ecoboost Fiesta has been showing up as three blocks, rather than four blocks and it's had me curious. I'm aware that three blocks is still within the 'OK' range on the dashboard but I'm slightly concerned that it's a sign of an issue.

I have opened the 'secret menu' to get the actual temperature readings and found that driving for 30 minutes on A roads gets me to a maximum of 81c, experienced only when performing an overtake at 60mph - 'Normal' driving sees the coolant temperature showing at around 72c. I've confirmed with a temperature gun that the hose is a couple degrees less than what the car is showing so I am assuming the temperature reading is correct.

Would it be wise for me to replace the thermostat, given I expect as we come into winter the temperature is likely to drop further which would be taking me into Fords recommended sub 70c for changing the thermostat.

Assuming that you have a 2015 Ecoboost 1.0 don't go looking for problems, they will find you fast enough. The secret menu is anything but secret, even my old granny knew about it. What it displays is not the same as what your temperature gauge sees. The ambient air temperature is getting colder, and here in the North East it was around 8^oC for most of the day so you can expect your car to take longer to warm up and to run slightly cooler.

If you feel the need to worry about things then now is a good time to start thinking about changing the wetbelts and spending around £1500 !!!

Which thermostat were you thinking of changing? 

The thermostat should keep the temp on the gauge absolutely steady (once the car has warmed up).

If it fluctuates, the stat probably IS stuck open. Mine used to vary depending on my driving and  hover around 70 - 80 deg. I got it changed and it now never deviates from 90 deg however I drive. 

50 minutes ago, unofix said:

and to run slightly cooler.

That's interesting, as my temp gauge shows the same temp regardless of ambient temp. Seems to be doing its job properly.

40 minutes ago, iantt said:

Which thermostat were you thinking of changing? 

I've read about two with the main one aiming for 92c, so my assumption is that one is the faulty one if I can't reach that temperature

17 minutes ago, alanfp said:

The thermostat should keep the temp on the gauge absolutely steady (once the car has warmed up).

If it fluctuates, the stat probably IS stuck open. Mine used to vary depending on my driving and  hover around 70 - 80 deg. I got it changed and it now never deviates from 90 deg however I drive. Around £180 supplied and fitted.

That sounds very similar to what I'm experiencing! I'm happy to change it myself, I just wanted to check that what I'm seeing is actually a likely problem

1 hour ago, unofix said:

Assuming that you have a 2015 Ecoboost 1.0 don't go looking for problems, they will find you fast enough. The secret menu is anything but secret, even my old granny knew about it. What it displays is not the same as what your temperature gauge sees. The ambient air temperature is getting colder, and here in the North East it was around 8^oC for most of the day so you can expect your car to take longer to warm up and to run slightly cooler.

If you feel the need to worry about things then now is a good time to start thinking about changing the wetbelts and spending around £1500 !!!

Isn't the purpose of the thermostat to regulate the temperature to a generally consistent state, in the case of the main one on the Fiesta about 92c - I'm in Cornwall so it was about 14c out today, I'd expect that once actually in winter when ambient temperature drops further still my coolant would drop another 14c which surely is much too low?

4 hours ago, 56KBs said:

I've been noticing recently that the temperature gauge in my 2015 Ecoboost Fiesta has been showing up as three blocks, rather than four blocks and it's had me curious. I'm aware that three blocks is still within the 'OK' range on the dashboard but I'm slightly concerned that it's a sign of an issue.

I have opened the 'secret menu' to get the actual temperature readings and found that driving for 30 minutes on A roads gets me to a maximum of 81c, experienced only when performing an overtake at 60mph - 'Normal' driving sees the coolant temperature showing at around 72c. I've confirmed with a temperature gun that the hose is a couple degrees less than what the car is showing so I am assuming the temperature reading is correct.

Would it be wise for me to replace the thermostat, given I expect as we come into winter the temperature is likely to drop further which would be taking me into Fords recommended sub 70c for changing the thermostat.

Had exactly these symptoms on my wife's 2013 Ecoboost a few years ago. For less than £20 I figured it was a worthwhile speculative fix so I popped a new thermostat in and it sorted it out. 

I always intended on measuring the opening/closing temperatures of the old stat but never got round to it.  From a cursory visual check there was nothing obviously wrong with it.

 

37 minutes ago, MJNewton said:

Had exactly these symptoms on my wife's 2013 Ecoboost a few years ago. For less than £20 I figured it was a worthwhile speculative fix so I popped a new thermostat in and it sorted it out. 

I always intended on measuring the opening/closing temperatures of the old stat but never got round to it.  From a cursory visual check there was nothing obviously wrong with it.

 

Great to hear - My follow-up if it was going to be the right fix is are there any brands to avoid? I was going to get a genuine one for £45 but thought aftermarket may be just as good for less cost

I went for a Gates one as thermostats are part of their core business and the brand is trustworthy. I don't know who the OEM supplier is. 

Just looked back at my records and it was Gates part code TH50292G1. If you were after a supplier I am finding Parts in Motion to be really good (and free delivery if you're happy to wait for 2nd class).

14 hours ago, alanfp said:

That's interesting, as my temp gauge shows the same temp regardless of ambient temp. Seems to be doing its job properly.

It's lying to you.  The dash gauge on modern cars doesn't generally show a live temp. 

It's designed to sit at 90c across a wide range of temp (potentially 80-95c) so the driver doesn't concerned about small variations.  If you read the live temp through OBD, you can get an accurate temp.

Got a genuine thermostat from Fords eBay account in offer for £25 - fitted it yesterday and it's fixed the issue! Dash was reading between 89-93c on the drive home.

 

Bit if a pain to get to for replacing as I had to take the battery + holder out to get access due to not having a 1/4" hex adaptor to socket/a 1/4" spanner to get in the tight space

Help please - so I have an 18 plate Fiesta 125 Titanium Ecoboost....I drove it on Saturday for over an hour and the temp gauge remained right at the very bottom, heating even on full was pretty much cold, increased fuel used and sluggish to drive.  Is this likely to be that the Temperature sensor valve is stuck open or is it something more serious??  Its booked in with the local Ford dealer for Monday.  Thanks