[AlanBDahl]

Today at the grocery store I noticed a small puddle of water under my 2014 ST. However I just assumed that it was either leftover from recent rains or was from someone else’s car. I headed home, about 2 miles, and started smelling coolant as I neared home. When I stopped steam came pouring out from under the hood and when I looked there was coolant everywhere. What possibly could have broken on a 3-year-old car that could do that? I have to assume that it’s not a hose unless I somehow punctured it so it has to be something more. AAA is towing it to the dealer today but it will be at least Tuesday before they can look it at.

Thankfully I have a reliable backup car, my 300,000 mile 1990 Mazda Miata to tide me until the ST is back. I’ve been considering replacing it with something slightly bigger anyway, Mazda 3 or 6 or maybe a Bolt so I won’t have to worry about overheating ever again.

 

[MrEss]

Please update us on the root cause of that coolant loss when you get word! My 16 Fiesta ST is going into the dealer service department for a TSB on the cooling fans not working unless the A/C is on. Overheating on these cars is a deathblow. The plastic coolant bottle is a time bomb too! Heat cycles and time will make that component much more problematic than heater hoses, tubes or the radiator hoses.the coolant reservoir on my mom's 13 Chevy Cruz with only 43k failed in September! Fortunately the puddle was spotted right away.

 

[AlanBDahl]

You know judging from where the coolant was it’s quite possible that the coolant tank failed. When I was looking I assumed that something lower sprayed up towards the coolant bottle, I never considered the possibility that it was the bottle that was the source of the leak.

I can’t see how I could have too many heat cycles even at 65k miles especially since I live in Seattle and it rarely gets very hot here. I doubt that I did any damage to the engine as I saw no lights on the dash to indicate high temps or low coolant and the drive was short enough (2 miles each way) that even if I did loose all the coolant the engine likely would not have overheated.

 

[AlanBDahl]

Just got the word, it was of all things the hard plastic line that attaches the coolant recovery bottle to the radiator. It cracked and caused the mess. It appears I lost nearly a gallon of coolant which explains the mess. Hopefully the engine didn't overheat. I never saw any lights but without a real temp gauge it's hard to know how close it got to tripping a light.

Plan is to replace the hose and fill with new coolant. $350 for the failure of a $20 part. Is there anything else I should consider doing at the same time?

 

[FiST_To_The_Clutch]

Get Ultragauge, it allowed me to monitor the exact coolant temp in F as well as Boost, Intake Manifold temp, temp of the device itself (so it doesn't overheat), etc. The closest I've ever got was around 229 F and it didn't trigger the overheat. Well that was before I did that radiator fan relay recall thingy as the fan won't ever kick in unless I turn on A/C or direct the regular fan towards the windshield set for 65 F temp or lower (weirdest thing I've ever seen in my life). Remember that our coolant system is pressurized to increases the boiling point of the coolant. Saw someone reporting reaching 245 which triggers overheating and causing dash temp gauges to go to full 8 bars. So safely 225 or below is acceptable...

 

[Xaros]

Hi I am new here.I have the fiesta st with mountune 215- i/c mountune- silicone coolant and air hoses and thermostat of motorad (90°c).(all the temperatures I saw and will be reported below was from obd2 port with obdlink mx reader and torque pro app)
Thermostat:
https://www.carid.com/2015-ford-fie...tandard-replacement-thermostat-107542398.html

I know that ford thermostat opens at 96°c and ford antifreeze is WSS - M 97 B 44-D. But here in Greece 9 months of the year we have ~35°c . so I start to change coolant and thermostat with same of the market.
coolant such amsoil coolant boost with district water only results no good for the price and all the time with no pressure to the gas my fan was always open.(fan 1speed start to 102°c)out the temperature was 9°c
Redline water wetter with district water only results normal. With 30°c out I was from 98°c to 102°c
Evans waterless coolant temperature's was from 100°c to 110°c with 10°c out.no good result for 150$ coolant and prep fluid first.
I try a G12 antifreeze and results was to blow up my silicone collar.
Has anyone try something with good results? I really want to know .I can not experiment anymore..