Ford fiesta ST 1.6ltr

[Sarah2511]

Ford fiesta ST 2013 (I think) has had it's solenoid bypass valve and thermostat replaced - has been overheating and going into limp mode when under load going up a hill at 100km and using the AC (Aus weather) after then replacing said thermo it seems to have been okay. Today it had only 2 bars left in thermostat before overheating... what is going on?

 

[TyphoonFiST]

Time for a Pumaspeed radiator* Also id be pressure checking the coolant system components.

 

[Magnetic]

Ford fiesta ST 2013 (I think) has had it's solenoid bypass valve and thermostat replaced - has been overheating and going into limp mode when under load going up a hill at 100km and using the AC (Aus weather) after then replacing said thermo it seems to have been okay. Today it had only 2 bars left in thermostat before overheating... what is going on?

This is the same thing that happened to me. I ended up replacing the radiator with a mishimoto since whoosh radiator was out of stock but during inspection my mechanic told me it was due to the expansion tank being faulty. I had already ordered the parts so just upgraded to fully correct the issue. It gets insanely hot in AZ anyway.

 

[Dialcaliper]

Ford fiesta ST 2013 (I think) has had it's solenoid bypass valve and thermostat replaced - has been overheating and going into limp mode when under load going up a hill at 100km and using the AC (Aus weather) after then replacing said thermo it seems to have been okay. Today it had only 2 bars left in thermostat before overheating... what is going on?

The stock radiator is crap. It’s the same radiator out of the base model 120hp Fiesta, no changes for the toasty turbo ST motor.

Especially driving hard and/or a long uphill you’ll get overheating. It’s especially bad if you have the A/C on - as soon as the compressor cycles on and the condenser heats up (which is in front of the radiator) the it can shoot from normal (middle of the gauge) to the overheat line in <1 min. I had it happen even at less than 80F/27C on a hard uphill. Turning the A/C off, the car made it up the hill barely without exceeding the “hot” line, but required a light pedal (staying out of boost)

You might gain a little margin with a proper vacuum bleed of the cooling system if there is still air in the system, which is difficult to get out, but in Australia summers, it probably won’t be enough. This car just has too small a radiator from from the factory.

Unless you’re willing to drive like your grandma with the A/C off (and maybe crank up the cabin heat to help pull heat out of the engine) when it’s really hot out, there’s an aftermarket/performance aluminum triple pass radiator in your future. Any stock or OEM type/cheap replacement radiator just isn’t able to fit enough cooling area in due to the cramped space where the radiator is installed on the car

Not sure what the most available unit is going to be in Australia. The best fitting, fewest hassles install is made by Mountune, but Pumaspeed, Mishimoto, Koyo and Whoosh all sell good units will all do the job. Some with more fiddly installation than others. Pro-Alloy makes a really nice one as well, but is significantly more expensive than the others.

 

[rallytaff]

The stock radiator is crap. It’s the same radiator out of the base model 120hp Fiesta, no changes for the toasty turbo ST motor.

Especially driving hard and/or a long uphill you’ll get overheating. It’s especially bad if you have the A/C on - as soon as the compressor cycles on and the condenser heats up (which is in front of the radiator) the it can shoot from normal (middle of the gauge) to the overheat line in <1 min. I had it happen even at less than 80F/27C on a hard uphill. Turning the A/C off, the car made it up the hill barely without exceeding the “hot” line, but required a light pedal (staying out of boost)

You might gain a little margin with a proper vacuum bleed of the cooling system if there is still air in the system, which is difficult to get out, but in Australia summers, it probably won’t be enough. This car just has too small a radiator from from the factory.

Unless you’re willing to drive like your grandma with the A/C off (and maybe crank up the cabin heat to help pull heat out of the engine) when it’s really hot out, there’s an aftermarket/performance aluminum triple pass radiator in your future. Any stock or OEM type/cheap replacement radiator just isn’t able to fit enough cooling area in due to the cramped space where the radiator is installed on the car

Not sure what the most available unit is going to be in Australia. The best fitting, fewest hassles install is made by Mountune, but Pumaspeed, Mishimoto, Koyo and Whoosh all sell good units will all do the job. Some with more fiddly installation than others. Pro-Alloy makes a really nice one as well, but is significantly more expensive than the others.

I used my heater on full blast going up any steep hills, on my older cars, especially going to Vegas or towing up the incline on the 10 the other side of Palm Springs. Full blast of hot air with windows wide open until I reached the summits. It works!

 

[WannabeST]

I would start looking into a radiator and lower temp thermostat to swap in, in the mean time. When going up a hill, turn off the AC so you don't steal power from the engine and turn the heater on full blast to your windshield, hot air travels up so crack open the windows and it might save you a little heat. In my opinion a little bit of sweat is better than having to worry about over heating your car and blowing a head gasket or the whole motor.

 

[scooter123]

I have the Mouintune 3 pass and can recommend it highly. in 95 degree heat with the air conditioning running I can climb a 7% grade 4 miles long at 74 mph and see 4 bars in the temp indicator. BTW, that is exactly at 195 degrees where these engines are most efficient. When I installed this radiator I noted in immediate 3.5-4 mpg gain in fuel efficiency. Mileage on the way to a friends shop where we did the factory to Mountune swap I was getting 35 mpg and going home I was getting 39 mpg. The only downside is that when it's cold the engine takes longer to get warmed up and these cars drink gasoline when they are cold.

Since Mountune started out in the UK I would expect that their products will be easier to find down under so do a bit of looking. BTW, you'll also want to purchase a vacuum filler system, they are great at reducing the trapped air bubble in the radiator.

 

[Dialcaliper]

I have the Mouintune 3 pass and can recommend it highly. in 95 degree heat with the air conditioning running I can climb a 7% grade 4 miles long at 74 mph and see 4 bars in the temp indicator. BTW, that is exactly at 195 degrees where these engines are most efficient. When I installed this radiator I noted in immediate 3.5-4 mpg gain in fuel efficiency. Mileage on the way to a friends shop where we did the factory to Mountune swap I was getting 35 mpg and going home I was getting 39 mpg. The only downside is that when it's cold the engine takes longer to get warmed up and these cars drink gasoline when they are cold.

Since Mountune started out in the UK I would expect that their products will be easier to find down under so do a bit of looking. BTW, you'll also want to purchase a vacuum filler system, they are great at reducing the trapped air bubble in the radiator.

After installing the Mountune, my overheating issues have totally gone away even flogging the car hard.

Strongly agree on the vacuum fill/bleeder kit. The cooling system is almost impossible to remove all the air without it, even with the little bleeder on top of the radiator. The biggest problem area is the line/valve going to the heater core, which goes up then down and won’t bleed out easily by itself (resulting in the heater not getting hot)