Coolant Temps Still High After Installing Mountune Radiator

[drewcrolwey]

I installed my Mountune radiator in my 2016 Fiesta ST this past winter. Radiator works excellent during normal driving and is definitely an improvement over the stock radiator. The car doesn't overheat when being driven even moderately hard like it used to but still runs a little hotter than Id like. At a recent track day at Lime Rock the car peaked at 230 degrees F on the accesport. (It was about 75-80 degrees that day). The temp gauge in the car was still in the bars and the car didn't go into limp mode so thats alright. Anyone else with this radiator see tempos this high on track or should I look into this issue?

 

[drewcrolwey]

Car is not heavily modified only has a Mountune MP215 kit on it.

 

[TyphoonFiST]

Did you change out the Thermostat also to a 180 degree?

 

[KyleS]

I see similar results. When I had my radiator installed by Mountune they mentioned that it wont fix the cooling issues completely by itself but will allow more hot laps before getting up to a dnagerous temp. 230 is about the hottest I can get it though through a 20 min session in 100° weather. Trying an oil cooler next before hacking up the hood.

 

[MRX330]

Air bubbles need burping maybe? I was driving along and had the regular 198 coolant and 210 oil temps and out of nowhere coolant spiked to 234. Burped and filled until she puked out the rad and it’s all good now. The radiator won’t be as good as advertised until all the air is out.

 

[drewcrolwey]

Did you change out the Thermostat also to a 180 degree?

Nope, stock thermostat.

 

[B18_Spoon]

I drive my 2017 Fiesta between 200 and 550 miles for work everyday and I can tell u that the stock Ford thermostat acts up. I currently have 131k miles on it. Since the day I bought it (with zero miles) I've burped it, replaced the Rad, replaced the thermo, run different coolants.. NOTHING MATTERED. For some reason (out of nowhere!) The temp randomly spikes. So what I've been doing the past 6 months (only happened 1 or twice), is I turn the heater on full blast and blip the throttle gently a few times and the temps come back down instantly. It's the only way I've been able to deal with this so far.

 

[MRX330]

I drive my 2017 Fiesta between 200 and 550 miles for work everyday and I can tell u that the stock Ford thermostat acts up. I currently have 131k miles on it. Since the day I bought it (with zero miles) I've burped it, replaced the Rad, replaced the thermo, run different coolants.. NOTHING MATTERED. For some reason (out of nowhere!) The temp randomly spikes. So what I've been doing the past 6 months (only happened 1 or twice), is I turn the heater on full blast and blip the throttle gently a few times and the temps come back down instantly. It's the only way I've been able to deal with this so far.

How did you burp it?

 

[Clint Beastwood]

Has anyone boiled their thermostat yet to visually confirm it opens at the temps it says it will? I thnk that still works with newer tstats.

 

[Clint Beastwood]

Has anyone boiled their thermostat yet to visually confirm it opens at the temps it says it will? I thnk that still works with newer tstats.

This might be a perfect use for a sous-vide cooker lol - with it's exact temp control you could bring it to 180 exactly, then step it up to see the progression.

 

[Dpro]

I drive my 2017 Fiesta between 200 and 550 miles for work everyday and I can tell u that the stock Ford thermostat acts up. I currently have 131k miles on it. Since the day I bought it (with zero miles) I've burped it, replaced the Rad, replaced the thermo, run different coolants.. NOTHING MATTERED. For some reason (out of nowhere!) The temp randomly spikes. So what I've been doing the past 6 months (only happened 1 or twice), is I turn the heater on full blast and blip the throttle gently a few times and the temps come back down instantly. It's the only way I've been able to deal with this so far.

Ones thermostat does not act up like Krug said its a mechanical device it opens or does not open or sticks partially open. It does not doe all that stuff randomly. What you are describing is an issue with your whole cooling system. What year is your car? If its a 2014-2015 there is a know issue and its a combo of head and coolant line. Fords fix is to put in another temp sensor and a different line.
Sometimes they have replaced the heads on peoples engines due to castrophic failure under warranty on those years.
Supposedly their is a new part number for the later heads but no one has confirmed the heads actually are different cooling chamber wise.

I have not, but I do have my factory thermostat hanging out in a box with all the other parts I've pulled off. So... I suppose I could perform this test at some point.

This would be cool what year is your car?

 

[MRX330]

The new head is different and a different number. The old number was discontinued. This was according to the parts guy at a Ford dealer in Florida I bought the new head from for my build.

 

[Dpro]

The new head is different and a different number. The old number was discontinued. This was according to the parts guy at a Ford dealer in Florida I bought the new head from for my build.

Cool I thought so, thanks for the definite confirmation of that.

 

[nickstewartroc]

I installed my Mountune radiator in my 2016 Fiesta ST this past winter. Radiator works excellent during normal driving and is definitely an improvement over the stock radiator. The car doesn't overheat when being driven even moderately hard like it used to but still runs a little hotter than Id like. At a recent track day at Lime Rock the car peaked at 230 degrees F on the accesport. (It was about 75-80 degrees that day). The temp gauge in the car was still in the bars and the car didn't go into limp mode so thats alright. Anyone else with this radiator see tempos this high on track or should I look into this issue?

What year FiST do you have? I have a 16' and after replacing the radiator I had the same issue, then found out about the recall/tsb on the cooling fan relay and sure enough mine was melted so sometimes the fan would kick on and sometimes it wouldn't

 

[drewcrolwey]

What year FiST do you have? I have a 16' and after replacing the radiator I had the same issue, then found out about the recall/tsb on the cooling fan relay and sure enough mine was melted so sometimes the fan would kick on and sometimes it wouldn't

Mines a 2016, the fan works great, I looked into that relay issue but my car is good on that. The car hasn’t overheated but 230 definitely seems a little warm.

 

[johnny5]

I have the same issue with a mountune rad, airtech oil cooler, whoosh v2 intercooler. After a lap or 2 I'm up to 225, and hit 230. Going to try hood vents next.

On the street I'm 184-192.

 

[haste]

Good lord, pounding the crap out of my car at VIR in 85F weather with stock rad and cobb stage 3 tune, coolant temp only hit 225F. VIR is a fast track so the extra airflow may have helped but a majority of the lap is full throttle.

I do find the various reported cooling issues with the FiST odd...

I have yet to hit the track again with upgraded turbo and mishimoto radiator.

Edit: Just realized this post is old.

 

[TemecFist]

Air bubbles need burping maybe? I was driving along and had the regular 198 coolant and 210 oil temps and out of nowhere coolant spiked to 234. Burped and filled until she puked out the rad and it’s all good now. The radiator won’t be as good as advertised until all the air is out.

THIS......100%