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Engine Overheating

Messages
8
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0
Location
Atlanta, GA, USA
#1
Hey guys so today my engine decided to overheat. I have a 2017 FiST. It has mishimoto intercooler, woosh catless downpipe, MBRP catback exhaust and a 93 oct tune with LOUD crackle pop tune from Stratified. The temp outside here was around 95 I wasnt being too agressive with the car. I looked on the accessport and the oil temp was around 230 and i didnt get a chance to see engine temp or coolant temp. The coolant was boiling over. I havent had this issue before but i installed the Woosh downpipe yesterday and this is the first time its happened. Not sure if it related 🤔 The only thing i can think of is that it has something to do with the heat shields I took off of the old cat but no where to install on the new one. Orrrrrrr a possible bad thermostat? Pls help!
 


SrsBsns

Active member
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Location
San Diego
#2
Downpipe shouldn't have any affect on the temps. I don't think it would be related to the heat shields but it's strange that you already have an aftermarket rad.

I would check for leaks/air in the system.

Could also be the thermostat. You can run the car and when it gets to operating temperature, touch/squeeze the upper hose to see if it's warm and has coolant running through it or if it's empty. If it's cool/empty, it's thermostat time.
 


OP
T
Messages
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Location
Atlanta, GA, USA
Thread Starter #3
Yeah Im gonna check that tomorrow and see it was far to hot to touch today. I dont have an aftermerket rad yet just a intercooler.
 


Messages
438
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404
Location
Osage Beach, MO, USA
#5
230 isn't too hot for oil. But was the coolant really boiling out? If so, where was it coming from? You might just have a coolant leak.

On the other hand, look for things you might have disconnected/disturbed while doing the downpipe. Like a plug to the electric fan or something similar.
 


SrsBsns

Active member
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Location
San Diego
#6
Yeah Im gonna check that tomorrow and see it was far to hot to touch today. I dont have an aftermerket rad yet just a intercooler.
Oh, I saw Mishimoto and just automatically read radiator for some reason. Reading is hard...

It's well documented that the stock cooling system on these cars are bad. The stock radiator is terrible.
 


jayrod1980

Active member
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181
Location
Viva Las Vegas!
#7
It’s your stock radiator. It cooks when tuned, along with a larger bar and plate IC possibly blocking air flow. If you have the cash, I highly recommend getting the Mountune radiator. It fits like stock, Is a triple-pass, and can be installed without removing your bumper. Just make sure to buy a stock Fiesta drain plug so you don’t risk breaking it getting it out of the stock radiator.

As a band-aid, drain out your coolant and try doing 25 or 30% coolant to distilled water in it instead of 50/50. That helped a little bit before I swapped out the radiator. It really is maxed out when stock.

The Mountune radiator was the best upgrade to my car outside of tune and intercooler and I feel 100% necessary.
 


jayrod1980

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Viva Las Vegas!
#8
Also, you really need those heat shields in place or you are further flooding the engine bay with more heat. Make sure your electric fan fuse isn’t burnt up too. I don’t know if the 2017s have an issue, but when I first had overheating problems I changed it out for a bigger one, can’t remember if it was a recall or not, but I was looking for anything to help with overheating. Only the radiator swap fixed it for good.
 


OP
T
Messages
8
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Location
Atlanta, GA, USA
Thread Starter #9
Also, you really need those heat shields in place or you are further flooding the engine bay with more heat. Make sure your electric fan fuse isn’t burnt up too. I don’t know if the 2017s have an issue, but when I first had overheating problems I changed it out for a bigger one, can’t remember if it was a recall or not, but I was looking for anything to help with overheating. Only the radiator swap fixed it for good.
Thank you for all this info im gonna invest in a radiator then and a new thermostat from mishimoto since it wont hurt to have it open at 160°f as opposed to 207°f with stock thermo. Im not sure how to get the heat shields back in since they use to mount to the stock cat but there is no where to mount them on the new one. I might so it ghetto just so its there atleast to prevent heatsoak. Thank you again!
 


jayrod1980

Active member
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Location
Viva Las Vegas!
#10
Thank you for all this info im gonna invest in a radiator then and a new thermostat from mishimoto since it wont hurt to have it open at 160°f as opposed to 207°f with stock thermo. Im not sure how to get the heat shields back in since they use to mount to the stock cat but there is no where to mount them on the new one. I might so it ghetto just so its there atleast to prevent heatsoak. Thank you again!
I misunderstood... I thought you were talking about the exhaust manifold heat shield. I’ve not needed the colder temp sensor since getting the Mountune radiator. I personally wouldn’t do that unless you track all the time and it’s a pain to install.
 


Messages
49
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17
Location
Denton, MD, USA
#12
So I'm seeing temps upwards of 225 F.. the only thing I can think of is my previous accident, where I got shoved into someone and it shoved my radiator to about 2 inches from my block.. haha, yay, cars..
 


SrsBsns

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San Diego
#13
So I'm seeing temps upwards of 225 F.. the only thing I can think of is my previous accident, where I got shoved into someone and it shoved my radiator to about 2 inches from my block.. haha, yay, cars..
I saw temps that high almost daily while commuting and getting stuck in traffic.
Mountune radiator has me running under 190 all day now. Can't recommend it enough.
 


Messages
246
Likes
255
Location
Virginia
#14
I saw temps that high almost daily while commuting and getting stuck in traffic.
Mountune radiator has me running under 190 all day now. Can't recommend it enough.
Main issue right now is they are deeply backordered. I'm still waiting on mine, which I ordered three weeks ago.
 


The Cuzi

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Premium Account
Messages
261
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263
Location
Northern, Virginia, USA
#15
Thank you for all this info im gonna invest in a radiator then and a new thermostat from mishimoto since it wont hurt to have it open at 160°f as opposed to 207°f with stock thermo. Im not sure how to get the heat shields back in since they use to mount to the stock cat but there is no where to mount them on the new one. I might so it ghetto just so its there atleast to prevent heatsoak. Thank you again!
I would highly recommend not going to a 160°f thermostat. Folks on here will bite your head off over the 160°f vs 180°f vs stock thermostat. I did the mountune radiator install and was going to do the motorcraft 180°f thermostat next. The mountune radiator completely solved the overheating issue on my end. Even with the days hot as hell, I rarely if ever see anything above 199.9 (with stock thermostat) after the mountune radiator upgrade. The thermostat is a step further than what would normally be needed but that is my $0.02. Hope you're able to sort this out, that is a pain to deal with, concerning, and frustrating.
 


Ludeem1

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Premium Account
Messages
106
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146
Location
Ontario, CA, USA
#18
Definitely what the others have said, the tune makes it run hotter. When I installed my CPE I noticed a 2 degree temp increase at idle. It’s been hot here in south Cali and I’ve never seen the temps above 200.
 


Messages
247
Likes
209
Location
Metro Detroit
#19
Another fan of Mountune here. I don't use my air conditioning very often, just enough to keep it working. As a result I never hear my fan running since installing a Mountune radiator. 95 degree heat, fan does not run. One other thing I didn't expect is a 3 mpg gain in my city fuel economy. Prior to installing the Mountune radiator I was averaging about 31-32 mpg, after installing the Mountune I've been averaging 34-35 mpg.
 


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