Are these cylinder head temps high?

[sldghmr]

/\/\ This /\/\ Let's make sure 'something' fan-wise is working first....

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[ay1820]

So we have nice cool weather here today, with air temps of about 72 deg. I took the car for a bit of ride and was seeing inlet air temps pretty consistently of 77 deg, occasionally going up to 79. Driving around on more or less level roads, I was seeing CHTs of 198 deg consistently. Climbing up the hill I mentioned yesterday, the CHTs go up to 210 deg and stayed there for the duration (~3.5 miles), but dropped off quickly to 198 as soon as the road leveled out again.

Once I got home, I put the A/C on Max and checked the fans. The right side (smaller) fan was running, but the larger left side fan was not.

Overall, this seems like it may be borderline at most and probably not worth a service call. I will just keep an eye on it for a while and see if it gets any worse.

Thanks for the replies and the advice!

 

[Garfy]

Too rainy and wet for a long ride today, but after about 10 minute drive with CHTs of around 190, the fan was NOT running, so that may be my problem. The coolant temp gauge was right in the middle, like it always seems to be (I wish we had a readout option for coolant temp in addition to CHT). Will need to schedule a service call to have this checked.

Thanks again for the responses!

The thermostat is around 192-195F for most modern cars (they actually started using these temps back in the 90's as they wanted engines running hotter for emissions reasons). The old school "high temp" t/stat of 180 F is long gone. My car runs between 190-196F on normal cruise. BTW, when your temp shows 190 F, the fan will NOT be running as the thermostat opens a few degrees later and I'm guessing the fans won't come on until at least 200 F. Many older cars had fans that came on at 215 F which isn't that hot BTW. With a pressurized cooling system, even 220 F is not a problem when you realize that plain water boils at 212 F without pressure. With 15 psi or more of cooling system pressure, that boiling point of plain water exceeds 225 F; so with 50/50 coolant, your boiling point is significantly higher so I wouldn't worry about it. Your analog gauge reads 1/2 way which is normal. If it begins to go to 3/4 way up, I'd begin to get a little concerned.

 

[PoCoBob]

So what is the CHT actually measuring? Is it water temperature in the head? Oil temp in the head? Or the aluminum casting itself? And if it's the casting, where in the head? I'm sure the combustion chamber would read a lot hotter than cam shaft supports would.

 

[ay1820]

So what is the CHT actually measuring? Is it water temperature in the head? Oil temp in the head? Or the aluminum casting itself? And if it's the casting, where in the head? I'm sure the combustion chamber would read a lot hotter than cam shaft supports would.

I have been curious about that myself.

 

[PoCoBob]

I have been curious about that myself.

https://www.vehicleservicepros.com/...ng-fords-cylinder-head-temperature-cht-sensor
This is all I could find online. It does note that it was published 10 years ago so things may have changed since then. But it claims the sensor is measuring coolant temperature in the cylinder head and that info is used to control how the torque convertor in the transmission engages.

Either way, my owners manual states the engine will go into protection mode before any damage is done from high temps. My CHT looks very similar to what you posted and I have no fear about them being too high. I tend to believe what the engineers who built the product say and take whatever the internet experts say with a grain of salt.

 

[ay1820]

https://www.vehicleservicepros.com/...ng-fords-cylinder-head-temperature-cht-sensor
This is all I could find online. It does note that it was published 10 years ago so things may have changed since then. But it claims the sensor is measuring coolant temperature in the cylinder head and that info is used to control how the torque convertor in the transmission engages.

Either way, my owners manual states the engine will go into protection mode before any damage is done from high temps. My CHT looks very similar to what you posted and I have no fear about them being too high. I tend to believe what the engineers who built the product say and take whatever the internet experts say with a grain of salt.

Thanks for the info!

I agree that there is very little risk of damage. Since there is no info that I can find on what to expect, I was more interested to see how what I was observing compared to others.

 

[furdfan2018]

CHT is cylinder head temp. The sensor is in the back of the cylinder head and does not protrude into a wet coolant port meaning it measures the temperature of the aluminum head casting itself.

Measured CHT is typically about 10-11 degrees higher than actual coolant temp.

220 CHT is nothing to worry about as that would indicate your coolant temp is actually 209-210.

Enjoy the car, drive her.

 

[ice445]

Grille shutters strike again, haha. Non performance pack GT's run much warmer because of them. If you look through the grille you can see the flaps (they're fully open when the car is stationary or off). They block off some of the inlet airflow to reduce drag and improve MPG. This results in higher than expected cruising CHT's, especially going uphill. I suspect if you test temps with A/C on, they're a lot lower in general. This is because the shutters aren't allowed to close as much when A/C is running, and you get the low speed fan below 40mph which provides additional cooling.

As others have mentioned, this is completely normal and the car doesn't care in the slightest bit. Low speed fan for cooling purposes doesn't even switch on until 217. I've tested these extensively by locking them out, and with them open at all times, it's almost impossible to get the car to even hit 200 with normal driving, even on hot days. This is why there's so much variability on the forum with CHT values, Performance Pack cars don't have these shutters.

Also, I can confirm with absolute certainty that the stock thermostat for these cars is a 180F unit. If you ever take it out, its printed right on the face. The cooling system is entirely airflow limited.

 

[SensesFail]

Some spirited driving in SFL with IATs of 100+ degrees regularly (WHILE MOVING) has me between 212-225 temps on 2019 GT PP1

 

[WildHorse]

Non performance pack GT's run much warmer because of them.

What ? My non-performance pack ride I never see 200f CHT, even with the AC on it's at 198-199f. Temp gauge never goes past 1/2. Actually I'd call it never goes past a 1/3. Behind me upper grill is a rubber flap that covers just 1 row of honeycombs.

 

[ice445]

What ? My non-performance pack ride I never see 200f CHT, even with the AC on it's at 198-199f. Temp gauge never goes past 1/2. Actually I'd call it never goes past a 1/3. Behind me upper grill is a rubber flap that covers just 1 row of honeycombs.

15-17 gt doesn't have them either from what I've seen

 

[WildHorse]

15-17 gt doesn't have them either from what I've seen

Active shutters ?

 

[ice445]

Active shutters ?

Correct, that's what I'm referencing. The shutters cause base 18-23 gt's to run warmer despite the rad being able to do better

 

[WildHorse]

Correct, that's what I'm referencing. The shutters cause base 18-23 gt's to run warmer despite the rad being able to do better

Ahhh I see. Anyways, pretty sure 15-17 had AGS.

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