Thermostat/Temp Spike

[The_Big_Gingah]

2015 Fiesta ST, stock.

Three times since I've owned the car the coolant temperature gauge in the dash has spiked and the high temp warning light and tone came on. Within about 5 minutes the coolant temperature gauges begin to drop and within 10 minutes of the problem starting its back to operating temperature.

The most recent time I was in a position to safely pull over and open the hood. I didn't see anything out of the ordinary. There weren’t any obstructions to the radiator and the fan was turning. The ambient temperature was in the upper 80s. I was climbing a rather steep hill with switchbacks and was in 2nd. I cannot recognize any patterns or specific conditions which create it. I don't believe I've been on the highway when it's occurred.

I intend to check the thermostat and the whatever coolant temp sensor.

Has anyone else experienced this issue? Does anyone have any ideas on cause and solution?

Thanks for your consideration and help. Have a blessed day!

 

[TyphoonFiST]

Mountune Radiator....end it all already. Triple pass...complete work of art. Worth every penny. May still be able to use the Spring2019 code to get $112 off....good luck...you could also get new radiator hoses from Whoosh and a 180° for an extra $5.

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[maestromaestro]

2015 Fiesta ST, stock.

Three times since I've owned the car the coolant temperature gauge in the dash has spiked and the high temp warning light and tone came on. Within about 5 minutes the coolant temperature gauges begin to drop and within 10 minutes of the problem starting its back to operating temperature.

The most recent time I was in a position to safely pull over and open the hood. I didn't see anything out of the ordinary. There weren’t any obstructions to the radiator and the fan was turning. The ambient temperature was in the upper 80s. I was climbing a rather steep hill with switchbacks and was in 2nd. I cannot recognize any patterns or specific conditions which create it. I don't believe I've been on the highway when it's occurred.

I intend to check the thermostat and the whatever coolant temp sensor.

Has anyone else experienced this issue? Does anyone have any ideas on cause and solution?

Thanks for your consideration and help. Have a blessed day!

That's essentially stock behavior. These things overheat easily. Upper 80s, 2nd gear - a recipe for the limp mode.

A bigger radiator and/or an oil cooler is highly recommended. Mishimoto makes both. Or what @TyphoonFiST said.

 

[danbfree]

That's essentially stock behavior. These things overheat easily. Upper 80s, 2nd gear - a recipe for the limp mode.

A bigger radiator and/or an oil cooler is highly recommended. Mishimoto makes both. Or what @TyphoonFiST said.

Using a huge oil filter acts as a 2nd oil cooler, i've seen lower peak oil temps when really hot by 20 degrees, but coolant still struggling and that's far more important to keep down when full synthetic doesn't even remotely begin to break down until at LEAST 250 degrees. Fram TG or XG 3600 (never the shitty "PH" orange ones, only the silver/grey TG or gold XG synthetic models) if you have a stock radiator will fit at 4.96" long, also Wix 51516, (non-XP for better filtering at shorter OCI) and the same rebranded as NAPA Gold 1516 are ones just a bit shorter at 4.82" that should clear a thicker upgraded radiator... I know it doesn't make much sense, but using these oil filters over even the FL400S, which lowered oil temps a little, these bigger ones will help even further, I saw clear differences running each. The longer filter acts like a literal heat sink and takes about at least 4 more ounces of oil than the FL910S to help spread the heat around.

 

[Ford ST]

Mountune Radiator....end it all already. Triple pass...complete work of art. Worth every penny. May still be able to use the Spring2019 code to get $112 off....good luck...you could also get new radiator hoses from Whoosh and a 180° for an extra $5.

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I'm believe more and more everyday a radiator upgrading is absolutely a necessity. Have I installed one yet no. Will I install one eventually absolutely.


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[maestromaestro]

One way or another - if you are tracking your FiST, you'll need a radiator. And an oil cooler maybe...

 

[The_Big_Gingah]

Probably no track days in my future but I do like to get after it on Appalachian back roads.

I’ve begun to price out an upgraded radiator. Is there any danger in buying a used radiator? My main concern is damage I can’t see and missing parts.

 

[TyphoonFiST]

Probably no track days in my future but I do like to get after it on Appalachian back roads.

I’ve begun to price out an upgraded radiator. Is there any danger in buying a used radiator? My main concern is damage I can’t see and missing parts.

Not really anything to the Mountune radiator....or the mishimoto. Both are packed well unless this guy gets ahold of it.

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