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2016 fiesta st overheating

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Reason why, is because A/C on forces the high speed fan to run continuously. Thus you ensure air is pushed through the radiator 100% of the time. And as you know there's a lot of cooling taking place through the radiator on these cars.

Not to say the stock cooling system is sufficient in all track summer situations either
 


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Speed easy I am going to have to disagree with you. While it may turn one of the fans on, the additional load generates heat and more importantly, reduces power
 


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Agreed. But if your ac compressor can be tuned off under WOT, and you're on the track, it's not so bad. I would argue though you should save this life line for the cool down lap + the paddock area as your individual cooling needs may differ. But thats how I ran 5 20 min sessions in 90+ heat, and things for the most part went fine
 


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I removed the A/C on my boosted NA, but retained the A/C switch on the fan button. This allows me to do exactly what I think you wish you could, turn on that high powered Spal fan without the A/C robbing power.

You'll have to excuse my ignorance on the subject matter on FiSTs, because I am just now looking into these issues, but perhaps there is a way to tune the A/C so that it doesn't actually turn on, but the fan does?

Pull a fuse or something?
 


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I've never pulled a fuse on this car intentionally so I dont know what will happen. I guess with all this my hope is Ford engineers tuned in a wot a/c calibration state specification
 


alexrex20

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Reason why, is because A/C on forces the high speed fan to run continuously. Thus you ensure air is pushed through the radiator 100% of the time. And as you know there's a lot of cooling taking place through the radiator on these cars.

Not to say the stock cooling system is sufficient in all track summer situations either
I disagree. If your coolant temp is elevated your fans will be on Max anyway. All you're doing by turning on the AC also is heating up the air even more before it passes through the radiator. The air going through the radiator is first heated by the intercooler, then again by the AC condenser if you have the AC on.

And the fans do not run on Max anytime the AC is on.
 


alexrex20

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I removed the A/C on my boosted NA, but retained the A/C switch on the fan button. This allows me to do exactly what I think you wish you could, turn on that high powered Spal fan without the A/C robbing power.

You'll have to excuse my ignorance on the subject matter on FiSTs, because I am just now looking into these issues, but perhaps there is a way to tune the A/C so that it doesn't actually turn on, but the fan does?

Pull a fuse or something?
The computer is smart. It will turn the fans on if it needs them, whether or not the AC is on.
 


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I disagree. If your coolant temp is elevated your fans will be on Max anyway. All you're doing by turning on the AC also is heating up the air even more before it passes through the radiator. The air going through the radiator is first heated by the intercooler, then again by the AC condenser if you have the AC on.

And the fans do not run on Max anytime the AC is on.
Do you have ECU trace to confirm?
 


alexrex20

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No, do you? I live in Houston where the ambient temp has been 90+ for the past month or three. My AC hasn't turned off since February and I can confirm that the fans are not always on Max when the AC is on.

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I disagree. If your coolant temp is elevated your fans will be on Max anyway. All you're doing by turning on the AC also is heating up the air even more before it passes through the radiator. The air going through the radiator is first heated by the intercooler, then again by the AC condenser if you have the AC on.

And the fans do not run on Max anytime the AC is on.
Maybe not max. But its on as soon as the ac button is pressed.

Let me put it in context. Ive seen a 5.0 mustang drop coolant temps 240 down to 210 in a matter of 10 min sitting idle in the paddock area with nothing but the ac system on. The dude ran in group 1 prior to this and told me this is recommended procedure on all modern cars.

But go ahead and prove this hypothesis wrong
 


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Any and every vehicle I've driven, runs the fan whenever the A/C compressor is activated. (reason being, the A/C compressor could be damaged without it) Personally, A/C only belongs in my refrigerator so the only time I use it is with older passengers. But I'll look at confirm that the fan starts almost immediately following the A/C compressor.
 


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Also worth noting is the three air flaps built into the stock fan shroud
My car is missing one of them I wonder how much difference this makes... if were being perfectly honest and postulative lol
 


alexrex20

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Maybe not max. But its on as soon as the ac button is pressed.

Let me put it in context. Ive seen a 5.0 mustang drop coolant temps 240 down to 210 in a matter of 10 min sitting idle in the paddock area with nothing but the ac system on. The dude ran in group 1 prior to this and told me this is recommended procedure on all modern cars.

But go ahead and prove this hypothesis wrong
Where did I say the fans did not turn on with the AC? I said they're not on Max simply because the AC is on. Reading comprehension is your friend.

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alexrex20

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Any and every vehicle I've driven, runs the fan whenever the A/C compressor is activated. (reason being, the A/C compressor could be damaged without it) Personally, A/C only belongs in my refrigerator so the only time I use it is with older passengers. But I'll look at confirm that the fan starts almost immediately following the A/C compressor.
You are right that A fan is on whenever the AC is on. They aren't necessarily in high speed. The AC condenser needs air blowing through it, thus the fan turns on. In colder climates the car can run for a good long while with no fan on at all... As long as the AC is off.

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alexrex20

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Maybe not max. But its on as soon as the ac button is pressed.

Let me put it in context. Ive seen a 5.0 mustang drop coolant temps 240 down to 210 in a matter of 10 min sitting idle in the paddock area with nothing but the ac system on. The dude ran in group 1 prior to this and told me this is recommended procedure on all modern cars.

But go ahead and prove this hypothesis wrong
Speaking of proving hypotheses wrong, that Mustang would've dropped water temps with the AC off. Prove me wrong.

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Where did I say the fans did not turn on with the AC? I said they're not on Max simply because the AC is on. Reading comprehension is your friend.

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Hey if you have data to show for it one way or the other let's continue. Otherwise this is just a waste of energy
 


alexrex20

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Hey if you have data to show for it one way or the other let's continue. Otherwise this is just a waste of energy
For once you are correct.

If the engine is running, so is the water pump. If water temp is 240 then the tstat is open and water is circulating. Unless ambient temp is greater than 240F, then naturally the hot water in the radiator is going to radiate heat and drop temperature.

Argue all you want but if the water temp is 240 the computer will have both fans on, and at their highest speed. Do you really think you're smarter than the computer, or the Ford engineers? Do you really think that they would not have the fans run at 100% when it's overheating? Do cars without AC just have to live with overheating conditions because there's no magic button to turn on an extra fan?

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alexrex20

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I could take a video of my car whirring and howling (due to both fans at 100%) while idling in the parking lot when it's 100F outside, with the AC OFF and you still wouldn't believe it.

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Intuit

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Thought the Fiesta only had a single fan. Larger vehicles with automatic transmissions tend to have two.
Speed_Easy never said that you had to activate A/C to get the fan to run.
As we know, the engineers took a pretty passive approach to engine cooling; a mere 25% duty cycle at 220°F; finally a 100% duty cycle at 230°F.
His only point was that you might be able to get your fans to run at a higher speed sooner via activating the A/C.
But as someone pointed out, the A/C condensor sits in front of the engine radiator.
So testing would be needed to confirm whether that will have the desired impact.
 


alexrex20

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Thought the Fiesta only had a single fan. Larger vehicles with automatic transmissions tend to have two.
Speed_Easy never said that you had to activate A/C to get the fan to run.
As we know, the engineers took a pretty passive approach to engine cooling; a mere 25% duty cycle at 220°F; finally a 100% duty cycle at 230°F.
His only point was that you might be able to get your fans to run at a higher speed sooner via activating the A/C.
But as someone pointed out, the A/C condensor sits in front of the engine radiator.
So testing would be needed to confirm whether that will have the desired impact.
You're right, I think the fiesta only has one fan. It just has multiple speeds. But turning on the AC does not put the fan in maximum speed. Guaranteed.

Turning on the heater definitely does help cool down an overheating engine. That is hot coolant being pumped through the heater core with air blowing over it from the blower motor. Yes it will will heat you up, but it will cool down your car. That is a proven way to cool down an overheating engine. Turning on the AC is not.

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