St Coolant level stays under minimum

[areyes]

Hello! So i bought an ST a little over 4 months ago, iv been loving it. A couple months ago i did some sort of spirited driving uphill and the car overheated, threw a warning light, so i waited for the car to cool off, it leaked some fluid but that was it. i turned the car on and waited to see look for a leak but there was none to be found. fans worked everything seemed okay so i drove back home (2 hour drive) and everything was working normally. i couldnt live knowing the car could overheat when pushed so i upgraded the intercooler to a mountune and switched the thermostat for a 180 out of motorcraft. this was maybe 2 months ago. the car has been performing perfectly, iv been pushing it within city limits and its never over the desired temp. the coolant level was a bit under the minimum level, i didnt top it off but i kept my eyes on it everysingle day and it stays in the same spot. so last week i decided i felt comfortable with topping the level knowing it was leak free. today i checked the level and it was back at under the minimum level again, same spot as before. car is working perfectly, it doesnt go under that level. do you guys have any input in this? i am going to top it off again today after work but i dont know if its a normal fiesta thing or what. The car has no power loss, no leaks, its working at perfect temps (i keep an eye on them with an obd2), it just levels under minimum and stays there.

 

[Capri to ST]

I would recommend that you check and see if your car was subject to the recall. Some cars around the '14 and '15 model years were recalled for a defect in the head which could cause coolant leaking and overheating. If your car is subject to the recall and it hasn't been done, that could be a cause of your issues. Welcome to the forum and to ST ownership, it is an exceptionally fun car.

 

[areyes]

I would recommend that you check and see if your car was subject to the recall. Some cars around the '14 and '15 model years were recalled for a defect in the head which could cause coolant leaking and overheating. If your car is subject to the recall and it hasn't been done, that could be a cause of your issues. Welcome to the forum and to ST ownership, it is an exceptionally fun car.

Thank you, i love this car. But this small issues make me rethink about ownership. its had this issue and the hatch handle went crazy and now it only opens with the keyfob. No recalls on the car according to https://owner.ford.com/tools/account/maintenance/recalls.html

 

[SteveS]

It's also possible you just don't have the cooling system full yet. Since it's an overflow tank, it doesn't draw in until it's gotten hot and then cools down. And sometimes after the system is opened (like to replace a radiator) there may be pockets of air that have to make their way out. If you've only topped it off once, I'd try it again.

What year is the car? How many miles does it have on it?

 

[Capri to ST]

Thank you, i love this car. But this small issues make me rethink about ownership.

The cars have generally been quite reliable, there are many of them pushing 300 horsepower or more with no problems. There was one owner on here who reported 185,000 miles on his car with no issues. When I was researching the car, one thing that made me feel good about its expected durability was that the engines are used virtually stock in the Formula Ford racing series. I figured if they can stand up to the demands of racing, that they should certainly be able to take being driven hard on the street.
Finally there's this, my favorite Fiesta ST video. A professional rally driver notes that he uses a stock drivetrain in his rally Fiesta ST, and drives a stock model hard on a rally course without being able to break it, so don't lose hope

View: https://www.youtube.com/watch?v=kM1nkR8pkX4&list=FLur65YQuzud3gXqwZTZTrxQ&index=24&t=24s

 

[jeff]

To the OP, I don’t think you need to be concerned that the car won’t hold up long term, they have proven quite reliable and bulletproof for the most part. Exceptional in fact, I’ve been happily surprised.

The cars have generally been quite reliable, there are many of them pushing 300 horsepower or more with no problems. There was one owner on here who reported 185,000 miles on his car with no issues.

I think you’re talking about Brian, he’s at 220,000 now and still going strong...

 

[scooter123]

First, you replaced the radiator, not the intercooler. The radiator is what cools the Engine, the intercooler cools the intake charge.

Your overheating was caused by the factory choosing to use a radiator that has proven to be marginal in high heat situations and by replacing that radiator with one that has a larger cooling capacity you have solved that issue.

BTW, not a fan of changing the thermostat to a cooler one, with these engines that can result in some negative effects on some of the performance aspects. One will likely be a reduction in fuel economy. There is also the fact that doing this is probably a violation of the EPA regulations.

To sum it up your new radiator was the solution for a problem that is well known in the FiST community. The only other issue that you can expect to crop up is a failure of the motor for the Blend Door actuator, from what I've read those generally fail around 30,000 miles. BTW, there are two of these blend door actuators and one is easy to get at behind the cabin air filter. The other is a PITA and when it goes on my car I plan on cutting an access port into the under dash panel to make this area easier to service.

Seems to me a bit of a waste to give up on a great little car just because of a few minor issues. Especially after you've already fixed the major issue.

 

[AZSP33D]

The reservoir coolant level will move up and down a bit as you operate the car... the recall mentioned is just a sensor, doesn’t fix the problem, just reduces the risk a little bit from low coolant levels... but unless you have some damage from badly overheating (doubt it) it should be fine. Fill it up to the full mark and if you see it below, fill it to full again, and check often... you should get a sense of what’s going on if you do that. If you’re really really worried, drain all the coolant, and go through the process of changing out to Evans Waterless coolant. It doesn’t boil until like 370F and produces no pressure or stress on the cooling system. You will need well over a gallon. If anyone has questions about Evans or Propylene Glycol based coolant with no water added, let me know, I have many years and dozens of vehicles converted, and a good understanding of how it works and behaves and why. I’ve fixed many temperamental cooling systems with pure Propylene Glycol, with Evans, a combination, etc. The Ford F-250 6.4 Diesel has a cooling system problem that’s complex and multiple, and all was fixed. The Ducati 1098R would have issues putting around and now zero... both Fiesta ST’s have it. BUT it will not necessarily run cooler, it has less heat coefficient than water. Jay Leno uses it on all his vehicles BTW. It’s also safe and pure Propylene Glycol is edible... and also reduces toxicity of ethelyne glycol. Anyway, went off on a tangent but hope that helps.

 

[AZSP33D]

Oh... and if there’s some pressure/coolant loss, the plastic reservoir and thin plastic tubes are the likely culprits in my opinion.

 

[xxiaze]

Silly question maybe but did you burp the system well when you upgraded the radiator? It is possible it finally settled and that just happened to be where the coolant now resides before top off? Yes to previous suggestion of recall as well. I have a 14’ and my coolant rests where yours does. I have stock radiator. I would check for the recall to be performed and top off fluid. Between the 2 acts your vehicle should be stable. This, IMO, is no cause for concern. My vehicle is 100k+ and only issue is blend door clicks and vehicle stumbles on fuel fill up if I leave it running while fueling OR overfill/top off too much.

 

[areyes]

It's also possible you just don't have the cooling system full yet. Since it's an overflow tank, it doesn't draw in until it's gotten hot and then cools down. And sometimes after the system is opened (like to replace a radiator) there may be pockets of air that have to make their way out. If you've only topped it off once, I'd try it again.

What year is the car? How many miles does it have on it?

I believe this might be the culprit, i filled it out and its been staying in the max level. i guess im just really paranoid about my 8k miles car geeting overheated!

 

[areyes]

Silly question maybe but did you burp the system well when you upgraded the radiator? It is possible it finally settled and that just happened to be where the coolant now resides before top off? Yes to previous suggestion of recall as well. I have a 14’ and my coolant rests where yours does. I have stock radiator. I would check for the recall to be performed and top off fluid. Between the 2 acts your vehicle should be stable. This, IMO, is no cause for concern. My vehicle is 100k+ and only issue is blend door clicks and vehicle stumbles on fuel fill up if I leave it running while fueling OR overfill/top off too much.

It was done by a shop, the owner told me to keep an eye on it, otherwise to take the car back for a check up.

 

[areyes]

The reservoir coolant level will move up and down a bit as you operate the car... the recall mentioned is just a sensor, doesn’t fix the problem, just reduces the risk a little bit from low coolant levels... but unless you have some damage from badly overheating (doubt it) it should be fine. Fill it up to the full mark and if you see it below, fill it to full again, and check often... you should get a sense of what’s going on if you do that. If you’re really really worried, drain all the coolant, and go through the process of changing out to Evans Waterless coolant. It doesn’t boil until like 370F and produces no pressure or stress on the cooling system. You will need well over a gallon. If anyone has questions about Evans or Propylene Glycol based coolant with no water added, let me know, I have many years and dozens of vehicles converted, and a good understanding of how it works and behaves and why. I’ve fixed many temperamental cooling systems with pure Propylene Glycol, with Evans, a combination, etc. The Ford F-250 6.4 Diesel has a cooling system problem that’s complex and multiple, and all was fixed. The Ducati 1098R would have issues putting around and now zero... both Fiesta ST’s have it. BUT it will not necessarily run cooler, it has less heat coefficient than water. Jay Leno uses it on all his vehicles BTW. It’s also safe and pure Propylene Glycol is edible... and also reduces toxicity of ethelyne glycol. Anyway, went off on a tangent but hope that helps.

Thats quite interesting, i belive im just being paranoid as the level seems to be normalizing by bits, but im in colombia and we dont have access to this kind of specialized fluids, pretty interesting tho.

 

[areyes]

The cars have generally been quite reliable, there are many of them pushing 300 horsepower or more with no problems. There was one owner on here who reported 185,000 miles on his car with no issues. When I was researching the car, one thing that made me feel good about its expected durability was that the engines are used virtually stock in the Formula Ford racing series. I figured if they can stand up to the demands of racing, that they should certainly be able to take being driven hard on the street.
Finally there's this, my favorite Fiesta ST video. A professional rally driver notes that he uses a stock drivetrain in his rally Fiesta ST, and drives a stock model hard on a rally course without being able to break it, so don't lose hope

View: https://www.youtube.com/watch?v=kM1nkR8pkX4&list=FLur65YQuzud3gXqwZTZTrxQ&index=24&t=24s

Why did i never see this video?? i searched all around the internet and never saw this video or the overheating issue.

 

[Scotman2]

Silly question maybe but did you burp the system well when you upgraded the radiator? It is possible it finally settled and that just happened to be where the coolant now resides before top off? Yes to previous suggestion of recall as well. I have a 14’ and my coolant rests where yours does. I have stock radiator. I would check for the recall to be performed and top off fluid. Between the 2 acts your vehicle should be stable. This, IMO, is no cause for concern. My vehicle is 100k+ and only issue is blend door clicks and vehicle stumbles on fuel fill up if I leave it running while fueling OR overfill/top off too much.

My 2016 is perpetually sub maximum on coolant. That stumble or stalling on refueling at idle is not a "problem". It's a "situational condition" caused by fuel cavitation in the fuel pump and lines because air is being introduced as the fuel dumps in. Sometimes I have seen lean misfire codes triggered. It's nothing that can damage the engine. Cars are not engineered to be running when refueled.