Mountune Fiesta ST Radiator Upgrade

koozy

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Well I was personally referring to fully open. Sooo, my bad for not specifying [emoji23]
it's all good, just want to present what the manual actually states so we're all in agreement with something at least.
 


jayrod1980

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Cool... I stand corrected. Thank you for clarifying. I think still don't want to see 220F on the Accessport while on the highway. I usually don't see 220F sustained on the highway unless I'm traveling fast and oil temp shows 240F or so. Either way, in temperate times of the year coolant temps hover between 185 and 195F and oil temps don't go above 215F.

I wonder if all the individuals testifying as to the Mishi radiator staying under 200F have the lower temp thermostat as well. You'd think they would mention that.


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Cool... I stand corrected. Thank you for clarifying. I think still don't want to see 220F on the Accessport while on the highway. I usually don't see 220F sustained on the highway unless I'm traveling fast and oil temp shows 240F or so. Either way, in temperate times of the year coolant temps hover between 185 and 195F and oil temps don't go above 215F.

I wonder if all the individuals testifying as to the Mishi radiator staying under 200F have the lower temp thermostat as well. You'd think they would mention that.


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Mishi radiator owner here. I have stock thermostat and stay sub 200 in az. Although I haven't taken my access port on the highway. Mostly traffic and some mountain runs in the evening.


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Given the nature of our cooling system, I would hazard these people still seeing 200+ temps have an air pocket somewhere.

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Stock thermostat/Mishi here. I'm in Tx, and I see 185 to 195 on the AP no matter if I'm in town, highway, or what temperature outside. After startup, the temps will run up to 197-200, then will go down and settle to 185-195.
 


Ish

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Hottest I've seen on my mishimoto radiator is about 210-212, and that's with 120-125 degree that we get here in Palms Springs, CA. Car was idling for about 10-15mins after some city driving and temps slowly crept up to 210ish. Not to mention with about 20-30% percent humidity. Stock thermostat as well. On the fwy I'll see about 205 at the most and again that's with 120 degree temps. Just for comparison, On my stock radiator id be overheating with these temps.
 


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The FiST is a weekend car for me so I don't drive it all the time. I will take it to work Thursday morning. My morning commute is on a toll road (the 73 from fountain valley to Laguna for those of your in southern cali) which is constant 75 mph and has one decent hill and a few smaller ones. It's about a 25-30 min drive. I will set cruise at 75 and let you know the outside temp, coolant and oil temps. I never took any logs over the weekend. Those numbers are what I can recall from my memory which could be mistaken.
 


jayrod1980

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The FiST is a weekend car for me so I don't drive it all the time. I will take it to work Thursday morning. My morning commute is on a toll road (the 73 from fountain valley to Laguna for those of your in southern cali) which is constant 75 mph and has one decent hill and a few smaller ones. It's about a 25-30 min drive. I will set cruise at 75 and let you know the outside temp, coolant and oil temps. I never took any logs over the weekend. Those numbers are what I can recall from my memory which could be mistaken.
I appreciate the metrics. I'm from Orange County originally and have put a lot of miles on the stretch you are driving. It's pretty cool out though in the morning, and even in the afternoon with traffic it's not typically hotter than 90F. My radiator tends to work fine in anything 95F or below, but really is maxed out afterward. I'm hoping I can master the lift out the top method of radiator tomorrow night in time to have my car ready for my morning drive from Vegas down to Lake Havasu.

The Mountune radiator looks pretty nice and well-made from what I could tell taking it out of the box. I couldn't start the project tonight because I have work in the morning. Hoping to change out the radiator, install the DV+ diverter, a new set of spark plugs, and a new cabin filter in one go.
 


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I appreciate the metrics. I'm from Orange County originally and have put a lot of miles on the stretch you are driving. It's pretty cool out though in the morning, and even in the afternoon with traffic it's not typically hotter than 90F. My radiator tends to work fine in anything 95F or below, but really is maxed out afterward. I'm hoping I can master the lift out the top method of radiator tomorrow night in time to have my car ready for my morning drive from Vegas down to Lake Havasu.

The Mountune radiator looks pretty nice and well-made from what I could tell taking it out of the box. I couldn't start the project tonight because I have work in the morning. Hoping to change out the radiator, install the DV+ diverter, a new set of spark plugs, and a new cabin filter in one go.
Are you in the LVST/RS Facebook group in Vegas? I'm assuming you live in Vegas.

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A decent amount of traffic this morning before I got to the toll road. I am about 2-3 miles from the freeway and one I get on the freeway it's about a mile to the toll road. For those not living in Southern California. The toll is a few miles or straight followed by on few mile climb up a hill. I do not know the elevation change from bottom to top. Then down the first big hill to another smaller hill. Down that smaller hill to about a mile of flat to then another small hill where I eventually get off the toll. Here arm my readings per accessport. Vehicle is was 6th gear the entire time other then going up the first big hill where it was in 5th. Cursing speed was set at 75 mph the highest boost I saw from the entire 30 min trip was 8 psi. Outside temps ranges from 70-73 degrees from start to finish.

Vehicle does have an X-47 turbo and airtec intercooler.

Right before getting into freeway from surface streets.
Oil 175 / coolant 199

On freeway for mile before toll
Oil 190 / coolant 201

At the end of the few mile stretch of flat on toll road
Oil 217 / coolant 207

Almost at the top of the first big hill
Oil 233 / 208
* note that right as I reached the top there is a small flat section l, but almost as soon as I reached he top the coolant shot down to 202
At the bottom of the big hill
Oil 206 / coolant 197

Top of second smaller hill
Oil 217 / coolant 214

Down bottom of second hill and during flat section.
Oil 215 / coolant 199

Top of last hill before I got off.
Oil 223 / coolant 215.


I am going to take the freeway home which is almost all flat.
 


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Radiator installed today plus I added water wetter with 50/50 motorcraft mix to maximize any cooling benefits. Not many miles on it (30 miles) so I can't say if it's good or not yet.

Ride back home (88-90F ambient) coolant temps were shooting up and down like crazy. 181F cruising in traffic, about 3 min later temps were up to 198F (still in the same kind of traffic), and 3 min after that right back down to 183F. As I parked in my driveway temps stayed around 196F-199F. So yeah, not sure what was happening but I'll have a better idea tomorrow after the car cools down completely at night and take it for a drive in the morning.
 


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Radiator installed today plus I added water wetter with 50/50 motorcraft mix to maximize any cooling benefits. Not many miles on it (30 miles) so I can't say if it's good or not yet.

Ride back home (88-90F ambient) coolant temps were shooting up and down like crazy. 181F cruising in traffic, about 3 min later temps were up to 198F (still in the same kind of traffic), and 3 min after that right back down to 183F. As I parked in my driveway temps stayed around 196F-199F. So yeah, not sure what was happening but I'll have a better idea tomorrow after the car cools down completely at night and take it for a drive in the morning.
You just have some air bubbles they will work themselves out
 


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You just have some air bubbles they will work themselves out
I guess, I made sure to let the bleed screw open until coolant came out but maybe I have to do it again I'll wait until it's cold again.

Driving tonight temps are 84F outside and it's holding steady at 190F.
 


codestp202

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In comparison, I drove home at 85 mph for 3 hrs in over 107 degrees with the mishi unit, and my temps didn't go over 195-200
 


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I'm not a mishi fan boy at all. I just don't see why you wouldn't get the bigger unit that holds more coolant.
Because if the Mountune unit prevents overheating it would weigh 10-15 lbs less than the Mishimoto making it a win-win.
 


codestp202

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Because if the Mountune unit prevents overheating it would weigh 10-15 lbs less than the Mishimoto making it a win-win.
Fair point, but so far it doesn't seem like the Mountune unit would be sufficient for track use.
 


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On my freeway drive home at 75 mph the temps hovered around 220 oil and 205-207 coolant. The thing I find interesting is that the temps come down a lot quicker then with the stock unit. Both coolant and oil will shoot down in temp vs before where they would slowly come down.
 




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