2025 GT engine oil temp runs hot

[Billycar11]

Makes me wonder if my Dark Horse with the oil cooler is keeping the engine oil too cool when I am not on a race track.

i saw the video the other day and was thinking the same thing but i imagine 190ish is fine to evaporate most of the water out i do alot of 3 hr trips on the highway so should be fine

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[Westphal]

Is there a thermostat in the oil cooler to bypass it until the oil reaches a certain temperature? I know some aftermarket oil coolers have one.

 

[Junkyard Dog]

Is there a thermostat in the oil cooler to bypass it until the oil reaches a certain temperature? I know some aftermarket oil coolers have one.

https://www.mustang7g.com/forums/threads/oil-cooler-activation-deactivation.169518/

See post #6:

Yes, I do know for sure. The Dark Horse with the oil cooler does have a thermostatic Valve in the filter mount assembly. Although Ford does not announce the temperature of operation, I can verify that at the track the valve closes off the oil cooler flow @ 204°F. Understand this, Ford built this valve assembly to always allow some bypass into the cooler so there is never a thermal shock when it initially opens.​

​

#14 is the thermostatic valve​

 

[Junkyard Dog]

My oil is 190-195 all the time during normal driving. On the street, I have not managed to get it over 210°

 

[robvas]

My poor jeep never gets much above the 160's in the winter

 

[AZ_Ryan]

My oil is 190-195 all the time during normal driving. On the street, I have not managed to get it over 210°

Drive harder.

 

[rijndael]

@rijndael did you have the chance to finish your measurements ? Would be good so see the difference before and after the oil cooler installation. Thanks!

I have to redo some of it. The high temp tape I used to keep the thermocouple attached to the line didn't hold as well as I'd like and I think it skewed things.

 

[Garcia172]

Does the S650 actually have an oil temp sensor?

 

[Junkyard Dog]

Does the S650 actually have an oil temp sensor?

No.

 

[Junkyard Dog]

But I'm sure that install doesn't include a computer update for the oil temp algorithm.

There's no way for that to be done yet, by an end user or the dealer.

Right. So basically you just gotta have faith the money you spent is working.

I've taken inlet vs outlet temps, on the cooler itself, and can see it working. You can also see the temp drop on the filter housing itself.

With a temp gun? At idle?

I have used a temp gun and saw a diff/delta, but I'm in the process of doing it with a thermocouple as well.

...and what were the temps?

I have measured 148 vs 183 on the hoses coming out of the filter housing.
I typically see about a 25-30 degree drop across the cooler tubes, from one side to the other.

I'm working on getting data from a 4 channel thermocouple setup, and I'm hoping to get oil pan data too. I'll post more data then.

Just quoting all this here to make it easier for everybody to find and read in one place.

That is a 35° F temperature drop from the cooler, if I am reading rijndael's post correctly. But that oil is not very hot, and I imagine the car is sitting still when he is taking those readings.

 

[Junkyard Dog]

Does the Ford Racing cooler have any way to prevent cooling off already cold oil?

 

[HBABQ]

Okay…. Kinda long-ish post..

Yes, the Gen 4 (2024+) Coyote engine generally runs with higher oil and operating temperatures compared to the Gen 3 (2018–2023) Coyote, often sitting in the 210°F–230°F+ range under normal driving, with reports of higher temps in non-Performance Pack cars. This is considered normal by Ford for modern, high-compression aluminum engines. [1, 2, 3, 4]
Here is why the Gen 4 Coyote runs hotter:

• Dual Throttle Body Intake System: The Gen 4 features a new, more complex air induction system (dual throttle bodies and air boxes) designed for higher performance and emissions compliance. This system, combined with a more restrictive engine cover, can cause higher inlet air temperatures and overall engine bay heat management challenges compared to the simpler Gen 3 intake.

• Increased Compression and Power: The Gen 4 continues to push the limits of power output (up to 486 hp in the GT and 500 hp in the Dark Horse) from a 5.0L displacement, which inherently generates more heat energy.

• Revised Cylinder Heads & Oil Management: The Gen 4 features significantly different, more complex cylinder heads with updated camshaft towers and a redesigned rear cover. These design changes affect heat dissipation.

• Engine Tuning: The Gen 4 ECU (Engine Control Unit) is tuned to run at higher temperatures for improved fuel efficiency and lower emissions. [5, 6, 7, 8, 9]

While Gen 3 engines (2018–2023) also tend to run in the 200°F–210°F range, they often display slightly lower overall operating temperatures under similar driving conditions compared to the newer Gen 4, which is designed to handle higher operational heat. [4, 10]

///break ///

Short answer:
At 240 °F, a typical 5W‑30 is effectively operating squarely in 20‑weight territory — not just “close to” it. At that point, yes, it behaves much more like a 5W‑20 than a true 30‑weight.
Let’s put real numbers on it so this isn’t hand‑wavy.
1. Baseline: where a 5W‑30 starts
Under SAE J300, a 30‑weight is defined at 100 °C (212 °F):

• SAE 30: 9.3 – 12.5 cSt @ 212 °F
• SAE 20: 5.6 – 9.3 cSt @ 212 °F

Most modern full‑synthetic 5W‑30s (including Motorcraft):

• Sit around 10.5–11.5 cSt @ 212 °F
• Often closer to the lower half of the 30‑weight band

2. What happens between 230 °F → 240 °F
Oil viscosity does not fall linearly — it drops faster as temperature rises.
A conservative engineering rule of thumb in this range:

• Every +10 °F above 212 °F → ~7–10% viscosity loss
• Every +20 °F → ~15–20% loss

So starting with ~11.0 cSt at 212 °F:
At 230 °F (~+18 °F)

• ~10–15% loss
• ≈ 9.3–9.8 cSt
  → right on the SAE‑20 / SAE‑30 boundary

At 240 °F (~+28 °F)

• ~18–25% loss
• ≈ 8.2–9.0 cSt

That is fully inside SAE‑20 territory.
3. Direct comparison at 240 °F

Oil	Effective viscosity behavior
5W‑20 @ 212 °F	~8.2–8.8 cSt
5W‑30 @ 212 °F	~10.5–11.5 cSt
5W‑30 @ 240 °F	~8.2–9.0 cSt
0W‑40 @ 240 °F	~11–12 cSt
5W‑50 @ 240 °F	~16–18 cSt

So at 240 °F, a 5W‑30 is:

• Viscosity‑wise indistinguishable from a 5W‑20

4. Important nuance: why it still isn’t literally a 5W‑20
Even though the thickness is similar, a 5W‑30 still has:

• Higher HTHS viscosity than a 20‑weight
• A more robust additive package
• Better shear stability

That’s why it doesn’t instantly become unsafe — but the hydrodynamic film thickness (the thing that protects bearings and cam lobes) is now what a 20‑weight provides.
5. What this means in real engine terms
At 240 °F on 5W‑30:

• Oil pressure margin is reduced
• Bearing film thickness is reduced
• Cam phasers are relying more on pressure control than viscosity
• You’re operating outside the comfort zone Ford had in mind for continuous street use

This is exactly why:

• Ford jumps straight from 5W‑30 → 5W‑50
• Enthusiasts gravitate to 0W‑40 at sustained high temps

Bottom‑line answer
At 240 °F, a 5W‑30 is absolutely behaving like a 20‑weight oil.
It hasn’t “failed,” but it has lost the viscosity margin that made it a 30‑weight in the first place.
One‑sentence takeaway
230 °F puts 5W‑30 on the edge; 240 °F pushes it fully into 20‑weight behavior.

///break ///

My overall take.
The Gen3 and previous ran 5w20 for decades…. Since the Gen4 runs hotter on aberage they chose to go up to 5w30.. at the Gen4 avg temps the oil is operating with viscosity between a 30 & 20wt (if operating 230/250).

Why didn’t they just bump the weight up to a 40? I’d say two main reasons.
1.)The high temp range still has the viscosity of a 20-30 wt (note there are Gen3s out there with over 200K miles, which ran on 5w20)
2.)The cars with the PP would need a different weight oil. One could argue they should be on a 5w20…. As optimal operating temp for a 30wt is 212f I believe. But like our non-pp cars they get 5w30…. As long as they get beyond the 160-170s they will burn off condensation.. And the 5w30 honestly gives them huge margin for heavy track abuse…. so good on the guys that have the PP.

The Gen4 runs hotter…
Go with a full synthetic
And enjoy the car…. unless you’re in the 240s and above for long long periods of time.. But even in the 240s you are at the same viscosity as a 20wt oil.
Just run your AC for u non-pp folks.

Cheers from NM

Let the beatings commence

 

[Cz_Ziemniak]

Dual throttle bodies will not make the engine oil run hotter, lol

Fuckin AI, lmao

 

[HBABQ]

Dual throttle bodies will not make the engine oil run hotter, lol

Fuckin AI, lmao

Not well written…. but I believe its pint was higher inlet temps when compared to the 3rd gen…. but hey I could be wrong

 

[Stanzi]

Good God Almighty. Stop with the AI. This car has incredibly LOW inlet temps, the first car I’ve ever seen where often the IAT’s are LOWER than ambient.

smh - they run hot because there is no oil coolers on non PP and below trims, and the Coyote engine is a massive power plant in a small space.

it’s not rocket science.

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