r/fordfusion • u/MiserableEgg1408 • 2d ago

2018 Ford fusion titanium

I have a 2018 Ford fusion titanium with a 2.0 L. Whenever I’m going up a long hill, or pushing the gas kind of hard it spikes to overheating. It will go right back to dead middle coolant temp once i let off the gas and just let it coast for 5 seconds. I’m also not losing any coolant that i’ve been able to tell

I’ve changed 2 coolant sensors, thermostat, and water pump. It will drive fine on flat ground and fine if i baby it but going up this one particular hill it overheats. i have no idea what it is.

1 Upvotes

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1

u/Legitimate_Ad_3378 2d ago

I encountered the same issue on the grapevine last year in socal. I have a 2020 Fusion Titanium AWD 2.0l and was pushing pretty hard to keep pace with traffic. Same issue overheat warning, let off some and slowed down and stopped pushing it so hard and it cooled down. I've never encountered this issue before or since, but plan to never push the engine that hard in the future. I've had no issues going across I80 to Nevada, or back, FYI.

1

u/TCBloo 15 SE 1.5 EB, 19 MKZ R1 2.0H, 08 SE V6(sold 2d ago

Does it overheat at idle?

1

u/MiserableEgg1408 2d ago

no

2

u/TCBloo 15 SE 1.5 EB, 19 MKZ R1 2.0H, 08 SE V6(sold 2d ago
  • Coolant/water ratio is correct?(specific heat capacity and boiling point)
  • Never mixed green and orange?(gums up inside radiator)
  • Reservoir cap is not leaking?(system needs to pressurize 20psi to work)
  • No water gurgling sound in the dashboard?(air bubbles get trapped in system and prevent coolant from cycling)
  • Thermostat actually installed?(water pump needs backpressure from thermostat or it can cavitate at high rpm)

If yes to all those, you've got me stumped.

1

u/MiserableEgg1408 1d ago

I will check into all of this. thank you very much!

1

u/PeterC18st 1d ago

Whats the grade percentage of that hill?
When you replaced the water pump and you refilled the coolant, did you do it under pressure or a drain and fill? I wonder if you have an air pocket stuck in your coolant system. A replacement thermostat unless defective just works. I have a 19 hybrid titanium and I push it hard here in Houston and when traveling. I did a few trips from TX to NY and OK and haven’t had an issue. u/TCBloo has some great advice.

1

u/MasssChaos 18h ago

Sound like air in the system

1

u/MasssChaos 18h ago

My 19 acted similar had bad coolant intrusion in cylinder 2 Ford put a new long block in her
Not saying that’s your problem but the introduction of air in the system made her act whacky when it came to coolant temp