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2016 fiesta st overheating

green_henry

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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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... and the beauty of the Fiesta is that you can rotate the outer vents towards the windows so that most of the hot air vents outside. I ran my most recent HPDE session this way and didn't feel the heat at all.
 


alexrex20

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... and the beauty of the Fiesta is that you can rotate the outer vents towards the windows so that most of the hot air vents outside. I ran my most recent HPDE session this way and didn't feel the heat at all.
Ya that's the ONE good thing about those idiotic vents. I run my track days in full heater. It gets hot but not as hot as me if I have to sit out an entire session to let it cool down. I can only track this car in fall/winter when ambient is less than 80.

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Intuit

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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.
My previous Ford also had a single fan. I didn't even know it had a high speed until two or three years of ownership. It always ran on low, even with the A/C engaged. It almost never ran hot enough to activate high. Once I heard it, named the high speed, "wind tunnel" speed. Shorts on, could be standing at the rear of the vehicle and feel the hot air rushing past the hairs on my legs.

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.
From one vehicle to the next, the effectiveness of running the heater has been debated, but this has otherwise been the accepted norm. It would be interesting to know what the minimum programmed duty cycle percentage is for fan operation with the A/C compressor engaged.
 


alexrex20

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If you have a major cooling system malfunction then I don't think running the heater will overcome anything. But air blowing over a heat exchanger will without a doubt cool the medium flowing through it - in this case coolant. I've seen first hand on many occassions how quickly it will drop water temp once you turn the heater on.

As for the wind tunnel mode, you ain't lying! It sounds like an airliner gassing up to taxi. I reckon many folks can go through their entire ownership without it ever going into wind tunnel mode. But down here it will sit on Max and still struggle to keep water temp under 220, especially in traffic.

Mountune radiator is my next mod for sure. I am able to get it full hot (max bars and warning light/chime but not in limp mode yet) just by hooning around on the street for a few minutes/miles in ~100F ambient.

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M-Sport fan

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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.
Since the engineers set those fan duty cycle temps sooo high mostly for EPA/CAFE reasons, WE have to figure out a way to either 'write in' via a tune, or over ride the ECU with a physical switch in order to get that 100% fan duty cycle ANYTIME we want it, again, IF this is even possible with Ford's encrypted (I'm guessing for some programs/systems directly effecting their EPA/CAFE compliance?) ECU.
 


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Since the engineers set those fan duty cycle temps sooo high mostly for EPA/CAFE reasons, WE have to figure out a way to either 'write in' via a tune, or over ride the ECU with a physical switch in order to get that 100% fan duty cycle ANYTIME we want it, again, IF this is even possible with Ford's encrypted (I'm guessing for some programs/systems directly effecting their EPA/CAFE compliance?) ECU.
While not exactly what you are going after, stratified does change the mapping of the fan speed on their tunes.
 


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that doesn't help us who need to run base tunes for classing purposes

I think radiator upgrades are out of the question. Probably the same for anything t-stat related.

I'm allowed to change coolant and oil, that's pretty much it. I'll try running some water wetter and get a good coolant flush done.

I'd also argue that the Mustang dropped temps due to SITTING in the paddock for 10 MIN. The fans should really be able to drop that temp much faster than 10 min.
 


Intuit

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Since the engineers set those fan duty cycle temps sooo high mostly for EPA/CAFE reasons, WE have to figure out a way to either 'write in' via a tune, or over ride the ECU with a physical switch in order to get that 100% fan duty cycle ANYTIME we want it, again, IF this is even possible with Ford's encrypted (I'm guessing for some programs/systems directly effecting their EPA/CAFE compliance?) ECU.
http://www.fiestastforum.com/forum/...western-states?p=298199&viewfull=1#post298199

Yeah, I *absolutely* do not want to mess with the stock mappings. The *only* part I'd want to tweak are the engine fan speeds.

I think the component that is missing from these charts, is barometric pressure. Regardless of ambient temperature, cooling at high humidity, sea level (0 ft) is going to be more efficient, versus cooling at low humidity, high altitude (5,000 ft). https://www.engineeringtoolbox.com/air-altitude-pressure-d_462.html 14.7PSI @ 0ft -vs- 12.2PSI @ 5,000ft elevation; a 17% change. We're at 500ft.



For starters, this is stock...
Code:
	180°F	190°F	210°F	215°F	220°F	230°F	Coolant
24°F	0%	0%	0%	10%	20%	100%	
50°F	0%	0%	0%	10%	20%	100%	
70°F	0%	3%	3%	15%	20%	100%	
80°F	0%	3%	3%	15%	25%	100%	
90°F	0%	3%	3%	15%	30%	100%	
110°F	0%	3%	3%	20%	30%	100%	
Ambient
As purely unscientific as possible... I'd want to test the tweak of... (more of an active vs passive cooling scheme)
Code:
	180°F	190°F	210°F	215°F	220°F	230°F	Coolant
24°F	0%	0%	0%	10%	20%	100%	
50°F	0%	0%	0%	10%	20%	100%	
70°F	0%	3%	3%	35%	75%	100%	
80°F	0%	3%	10%	40%	80%	100%	
90°F	0%	3%	15%	50%	90%	100%	
110°F	0%	3%	60%	90%	100%	100%	
Ambient
If someone sold a device for the strict purpose of tweaking fan temps, I'd consider snatching it; as I don't know any local tuners. (Brother might though.) I haven't experienced any temperature issues, but in such weather I am typically on the motorcycle.
 


alexrex20

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Ya that's pretty ridiculous that the fans don't go to wind tunnel mode until 230F regardless of ambient. Does that mean my car runs at 230+ because my fan is always in wind tunnel mode in the summer. The gauge sits pretty at 4 bar total (or 2 bars within the bracket) though.
 


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Yea i dont think it goes limp until 235 or 240, because when I parked in the paddock and checked temps on the AP, i was at ~231*F and power had already been restored
 


M-Sport fan

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While not exactly what you are going after, stratified does change the mapping of the fan speed on their tunes.
Yes, and IF I ever request another tune from them (or any of the others out there) this will be a REQUIRED change in order to purchase a tune from them.
(A new fan motor necessary because the factory one burned out due to running so hard/often STILL costs A HELLUVA LOT LE$$ than an engine rebuild/new long block, from a failed head gasket, or bent/broken, rods/pistons, due to being hydro-locked, etc. ;) )
 


alexrex20

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I'll have to monitor the next time my water goes full hot. The most I've seen was 225 and that was actually still showing as normal on the dummy gauge.
 


redmoe

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I think the stock gauge on mine would start moving from the center at 230 and would be outside of the "operational" zone above 240ish. The range is not linear at all.
 


Intuit

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It is well known that the temperature gauge is almost completely useless.
It's about as functional as a dummy light.
Think of it as a dummy light, rather than a gauge.
 


me32

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Yes, and IF I ever request another tune from them (or any of the others out there) this will be a REQUIRED change in order to purchase a tune from them.
(A new fan motor necessary because the factory one burned out due to running so hard/often STILL costs A HELLUVA LOT LE$$ than an engine rebuild/new long block, from a failed head gasket, or bent/broken, rods/pistons, due to being hydro-locked, etc. ;) )
Your fan motor burned out?
 


Quisp

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Okay yall, ive got good news for stockers out there, especially to fellow Texans.

Found it in the rulebook, for street class (HS) Thermostats may be substituted. Ordering my mishimoto now.
Do they do teardowns ? How would they ever know ?
 


alexrex20

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I didn't see anything about a larger radiator. If it doesn't specifically disallow it, then it's fair game. Right? ;)
 




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