Radiator/Cooling System Maintenance ("While I'm In There...")

[XanRules]

Hello all,

Just like my previous threads of "what to do while I'm in there..." I am, at some point, going to be replacing my cooling system just for longevity reasons in the near future as the car is coming up on 9 years/90k miles.

I have already replaced the coolant expansion tank and those hoses, I think it was either last year or the year before, just because they exploded on me.

My thinking is to replace the radiator and the two main radiator hoses (part numbers KM5220 and KM5218). Is there anything else that needs to be replaced?

I also see an "overflow" hose listed on RockAuto (KM6551) but I can't figure out where that would go, and then it looks like the "Air Aspiration" (KM5421) and the "Degas Feed" hose (KM5383). KM5421 looks like one of the expansion tank hoses I replaced last year, but I can't figure out where KM5383 would go or if I would need to do that, too. Any thoughts are appreciated.

Should I do the thermostat (Motorcraft 180 degree) while I am in there, or is that an entirely separate task that will not be made any easier by doing it while replacing the radiator hoses?

Thanks again as always! Pretty soon it's gonna be like a whole new car, and then I am sure someone will run a red light and t-bone me right after this is all done.

 

[Grsemky]

Hello all,

Just like my previous threads of "what to do while I'm in there..." I am, at some point, going to be replacing my cooling system just for longevity reasons in the near future as the car is coming up on 9 years/90k miles.

I have already replaced the coolant expansion tank and those hoses, I think it was either last year or the year before, just because they exploded on me.

My thinking is to replace the radiator and the two main radiator hoses (part numbers KM5220 and KM5218). Is there anything else that needs to be replaced?

I also see an "overflow" hose listed on RockAuto (KM6551) but I can't figure out where that would go, and then it looks like the "Air Aspiration" (KM5421) and the "Degas Feed" hose (KM5383). KM5421 looks like one of the expansion tank hoses I replaced last year, but I can't figure out where KM5383 would go or if I would need to do that, too. Any thoughts are appreciated.

Should I do the thermostat (Motorcraft 180 degree) while I am in there, or is that an entirely separate task that will not be made any easier by doing it while replacing the radiator hoses?

Thanks again as always! Pretty soon it's gonna be like a whole new car, and then I am sure someone will run a red light and t-bone me right after this is all done.

What year is your FiST? My '18 came factory with an 180⁰ stat and just upgrading my radiator was enough to keep me below 208⁰ even while idling with AC on in the desert...

 

[Stubborn Approach]

I recommend the Gates 180 thermostat which already comes installed in a housing vs the OEM thermostat. I did it at the same time as the radiator but you are coming up on the timing belt/water pump interval, so you could hold off to do it then instead.

 

[XanRules]

What year is your FiST? My '18 came factory with an 180⁰ stat and just upgrading my radiator was enough to keep me below 208⁰ even while idling with AC on in the desert...

2017.

I recommend the Gates 180 thermostat which already comes installed in a housing vs the OEM thermostat. I did it at the same time as the radiator but you are coming up on the timing belt/water pump interval, so you could hold off to do it then instead.

That's kind of what I was thinking, that I could hold off until then. In looking at the directions it seems like it's not really a "while doing the radiator" thing like it is on some cars, but rather a "while doing the belts" thing.

 

[Grsemky]

You might already have a lower temp thermostat from factory... Maybe see if there's a different part number for pre '16

 

[XanRules]

Looks like the 2017 part numbers are RT1211/BE8Z-8575-Z and the 180 degree is RT1241/BM5Z-8575-A. I'll take care of that when I do the belts.

 

[scooter123]

First off, if you are running a factory tune this engine operates most efficiently at 195 degrees. Back in the 70's and 80's we used to run 160 or 180 degree thermostats because the engines didn't have any Knock control or what we had was pretty damned poor. With today's engine controls we have more than enough Knock Control for these engines if they are operating at the DESIGNED optimum temperature. The problem with the FiST is that the Cooling System is undersized. Guess what, a lower temperature thermostat won't correct for that. Because wide open it can't do anything for cooling the engine because the radiator just isn't large enough. It's also a plastic radiator that will crack at some point and leave you broke down on the side of the road in a puddle of anti-freeze. Finally when it is cool enough so that thermostat can keep the engine at the thermostat rated temperature you will see a drop in Fuel Economy and Power Output.

One of the first things I did with my 2019 Fist within 2 weeks of delivery was to install a Mountune Radiator. As for how well it works, it is amazing. Hot 95 degree day heading west on I-64 out of Virginia there is a 5 mile incline going into West Virginia that is between 5 and 7 degrees. The engine temperature NEVER varied at all, it stayed at 4 bars in the indicator for the whole climb. In addition in the past 7 years the ONLY time the cooling fans come on is when I have the Air Conditioning on. The only downside is that in the winter it takes a long time to get the engine up to 4 bars and these cars drink gasoline like Cool Aid when they are cool. BTW if you don't know what Cool Aid is then google it.

BTW this radiator can push the fan shroud far enough towards the engine that it can rub on a cooling hose. So look closely and add some wire ties in the right spot to insure you aren't rubbing any hoses. Learned that lesson the "Hard Way". BTW you can patch one of these cooling hoses with a vulcanizing bicycle tube patch that is overwound with 6 layers of electrical tape pulled very taught. This can get you thru the 4 weeks it will take to get the complete assembly in from your dealer. I will also note that this hose can only be obtained by buying the entire assembly and that particular assembly requires removing the radiator. The hose alone can be replaced without removing anything except the old hose. As for the specific hose in question it come from the water tank over in front of the engine to a plastic housing in front of what I think may be the thermostat.

 

[XanRules]

I'm running an aftermarket tune, but that is a good point, I will check with my tuner and see if he recommends a specific thermostat.

I'm old enough to know what Kool-Aid is!
Appreciate the insight.

 

[Intuit]

Thanks again as always! Pretty soon it's gonna be like a whole new car, and then I am sure someone will run a red light and t-bone me right after this is all done.

...or you could order some nice EBC slotted rotors for it only to have the Amazon contractor delivery driver hit it while it's its perfectly parked minding its own business... then take off like nothing happened... sticking you with a bill over 5k. 🙄

note: you're free to laugh 🤭