Ford fiesta ST turbo 1.3 overheating after regular maintenance..

[Sarah2511]

Wf0cxxgakcej40399 vin -

Hi looking for advice....
My St has had cooling issues. Goes into limp mode but with no dashboard communication.

I've had my solenoid valve and thermostat replaced - had an at home computer diagnostics not find any fault codes. We get the car upto operating temp when it decides not to push through any coolant. Concerned it may have a cracked head. mechanic had trouble bleeding the system when replacing the overflow coolant reservoir.
I'm looking at having to go to my ford dealership to spend 300 aud just for them to look at it... any tips? I'm close to just limping the car into a ditch at this point.

Ford says my vin is outside the recall issue... are they playing dodgy or is it just terrible timing?

 

[SteveS]

I would be suspicious there is still air in the system.

 

[Dialcaliper]

I would be suspicious there is still air in the system.

I’d second this, the coolant systems on our cars are really difficult to bleed without a proper vacuum fill - did you bleed the little plastic valve on top of the radiator?

Even with a vacuum fill kit, I had to run the engine for a bit, wait for it to cool, then degas it multiple times to get the last bits of air out (pull vacuum till coolant starts foaming and let it sit like that for a minute or two, vent and repeat)

A hot air bubble in the wrong place can prevent flow if there is another route for coolant to travel - valve to the heater core and possibly the thermostat housing.

 

[scooter123]

A few notes.

First, these systems MUST be vacuum filled. Check to see if whoever swapped out the thermostat used a vacuum filler to put in the coolant. If they didn't you have an air bubble in your radiator that starts and the distance from the floor to the fill point for the reservoir. Use a tape measure and you'll find about 1/2 of your radiator is filled with air. BTW, I would suggest that you purchase a vacuum filler kit and an air compressor large enough to power it (1 1/2 hp or more). Then if you ever have to add coolant because the reservoir is low you'll be able to do it with the vacuum filler and insure you haven't developed an air bubble from the low fluid. Note, on my car there is a vent hole for the fill on the reservoir that I have to block with a piece of electrical tape for the vacuum to be developed. Note the point I tape is on the bottom of the reservoir.

Second, a lower temperature thermostat will not stop overheating issues. Because the radiator in these cars is just too small to be effective in some climate conditions. If it's over 90 degrees F and you push the car had it will overheat even if you have the thermostat glued wide open. I installed a Mountune 3 pass radiator in my ST and in 95 degree heat pulling a 7 1/2% grade for 5 miles the temperature indicators is nailed solid at 4 bars.

BTW my car still has the OEM thermostat and I don't see any need at all to change it. Power in full blast summer heat is torque limited by the tires in 2nd gear. In addition adding that Mountune radiator my fuel economy improved by 4 miles per gallon. The only downside to the over cooling capacity is these cars drink gasoline when cold so my winter mileage is not so great. Note my commute is on 5 miles, on a long trip where the engine can warm up fully the mileage runs between 36 and 42 mpg depending on how fast I'm driving.