thermostat advice

[ScaR]

I went to my mechanic to check as to why my car keeps overheating in stop and go traffic he's currently quoting me $603.44 to change

Temperature sensor
Thermostat
Antifreeze
Thermostat remove and replace.

I was considering on buying the parts myself so he can just install. I saw that there are two options the 180 or the mishimoto part which one would you guys recommend and why?

 

[Zeille]

an upgraded radiator and thermostat should do the trick. i wouldn't replace the temp sensor unless it's truly faulty. since you do those two things, you'll need to refill the system anyway.
is he replacing the radiator with an OEM unit? i would opt for an upgraded one from whoosh

 

[WannabeST]

an upgraded radiator and thermostat should do the trick. i wouldn't replace the temp sensor unless it's truly faulty. since you do those two things, you'll need to refill the system anyway.
is he replacing the radiator with an OEM unit? i would opt for an upgraded one from whoosh

I second this statement

 

[atlantaM3]

I would strongly suggest you go with the 180 Motorcraft unit, as I used a Mishi thermostat on a different car, and it was problematic. Ended up having to replace it.

Mountune also has Fiesta radiators, along with Mishimoto, Whoosh, etc. so several options available.

 

[ScaR]

That's t

an upgraded radiator and thermostat should do the trick. i wouldn't replace the temp sensor unless it's truly faulty. since you do those two things, you'll need to refill the system anyway.
is he replacing the radiator with an OEM unit? i would opt for an upgraded one from whoosh

That's the thing I'm confused about he said the radiator was fine?

 

[atlantaM3]

A full AL radiator is an upgrade that allows the car to handle heat more effectively, especially for tuned cars or those that are in 'hot/humid' climates. Many people have heat management issues in such places while running the A/C in heavy traffic.

The thinking is if you have the cooling system apart anyway, worth the extra $500-ish to add the extra cooling capacity. And they are fully metal, so no plastic endcaps to fail, so added reliability on a known failure area.

Also, add some WaterWetter, helps with heat transfer. Used it on other vehicles with notable improvement in cooling.

 

[ScaR]

A full AL radiator is an upgrade that allows the car to handle heat more effectively, especially for tuned cars or those that are in 'hot/humid' climates. Many people have heat management issues in such places while running the A/C in heavy traffic.

The thinking is if you have the cooling system apart anyway, worth the extra $500-ish to add the extra cooling capacity. And they are fully metal, so no plastic endcaps to fail, so added reliability on a known failure area.

Also, add some WaterWetter, helps with heat transfer. Used it on other vehicles with notable improvement in cooling.

So it's probably best to upgrade the radiator instead of doing that that with the thermostat is what your saying

 

[atlantaM3]

Generally, it seems that is what a lot of people do. I am personally doing both for my Fiesta, and did both in another current Ford car, and in other prior cars.

Personal experience - the radiator has a much larger impact to overall heat management, as it provides a better cooling function than the OEM unit due to it being larger and with an additional row vs stock. It is just a larger heatsink. The thermostat gives you added headroom in things like heavy traffic since it opens earlier so you get cooling sooner. But its the radiator that you want if you are planning to run the car hard somewhere hot, especially tuned.

It gets pretty hot where I am in the summer - but not as hot as where you are.

 

[atlantaM3]

to be clear, it is not a 'must', but it is not a bad idea.

 

[FlordPerformance]

The only thing I can offer on the thermostat issues it to when you buy new, you need to check thermostat with the boiling water test. cause if it doesn't open as it should you're never going to see it when it's installed in the engine..

 

[WannabeST]

So it's probably best to upgrade the radiator instead of doing that that with the thermostat is what your saying

Overall it is best to upgrade both.
Your radiator does little to no work when you are at a stand still. Which is why cars have fans, the fan helps pull air through the radiator to help get rid of heat. The lower temp thermostat will help circulate colder water while you are at a stand still/ lower speeds in order to keep the car cool.
And vice versa, your thermostat does little to nothing while your car is moving. Once your car is up to temp where the thermostat is open, it will just remain open. Once your thermostat is open, it is up to the radiator to help cool the car down. This is where you will see the benefits of the aluminum, because the added capacity of fluid, plus the addition heat dissipation from aluminum will help the car run much cooler.
For reference, in one of my dads work trucks, we swapped out only the radiator because it was getting hot while going up certain hills while towing. With the radiator swap alone, the temps went down roughly 15 degrees while towing on uphill. Temps at idle were borderline the same. Takes a touch longer to get fully up to temp but it is worth it.

 

[TyphoonFiST]

Does the Radiator Fan come on as it should? In stop and go traffic.

 

[Sam4]

Should also check that the mechanic will install your parts. Thats profit he's losing, which is a legit practice.

 

[Dialcaliper]

What everyone here is alluding to is that the stock radiator is undersized and inadequate for the turbocharged ST engine. Unless you’re tuning the car and driving it pretty hard, the “worst case” for cooling is the one you’ve described: Sitting still or stop and go traffic, hot days and A/C on. The A/C condenser in front of the radiator “preheats” the air coming into the radiator more than normal, and without moving at speed, the only airflow comes from the radiator fan.

The cooling system was designed for the stock 120hp Fiesta. Ford then went and tuned it up with a hot running little turbocharger, and obstructed the front even more with an intercooler (that also heats up air going into the condenser and radiator). Double whammy, and the stock radiator, even in top shape is inadequate. This is why Ford even resorted to limiting “overboost” to try and keep the heat down, because they were keeping costs down by not upgrading the radiator to a larger one. To give them some credit, odds are if they had an existing unit from a larger vehicle like the Focus/Fusion/SUV, they probably would have done so, but the Fiesta engine bay is just too small and a small, custom designed radiator for an ST model just wasn’t in the budget like it would be for a more expensive car like the Focus RS or a Shelby Mustang.

It’s not official or anything, but any “ST” car model, even the SUVs like the Exploder ST, basically means “parts bin special”. There are few to no parts on the car on any ST model that are bespoke to the car. Everything is either from the base model Fiesta, or a different existing vehicle, with some in-budget modifications allowed to make it fit, with a few things that are easy to source customized like the Recaro seats and a few interior parts and badges.