High Cylinder Head Temp - Not Overheating?

[wtfwork12]

Hello! I'm new to this form and I'm looking for some help.

I have a 2013 Mustang GT (non track pack) and 2 weeks ago I noticed my CHT was slowly approaching 223 F and then went to 235 F so I ended up replacing the following:

1. Water Pump
2. Thermostat
3. Cylinder Head Temperature Sensor

The car is still giving me a slow climb even at idle to 235 F and kinda stopping at 241 F on the CHT even after replacing all of the above.

• There are no leaks.
• Oil is fine
• Mechanic couldn't find anything with pressure test.
• The H and C is normal (which is weird because its a fake reading that's based off the high CHT)
• Oil temp is perfectly center in the green.
• Radiator fan turns on when with the AC off and it seemed at around 206-208 F
• Radiator fan also turns on with the AC on.
• Radiator fan will not shut off or cool the car down after it hits a CHT of 216-220 F.
• The heat works fine, AC works fine.
• Not that this matters, the radiator hose feels warm even when the CHT is above 220 F
• I took an infrared temp of the radiator after the car was running and the upper was showing 170F while the top right, bottom left, bottom right had a temp of 77F

This is becoming frustrating, could it be the radiator going out even with no leaks?

 

[gkomo]

Is 77 degrees normal on the ‘outgoing’ side of the radiator? Would make it seem as though the radiator is doing its job. Fan is actually pulling air through nicely?

 

[wtfwork12]

Is 77 degrees normal on the ‘outgoing’ side of the radiator? Would make it seem as though the radiator is doing its job. Fan is actually pulling air through nicely?

To be honest I have no idea, this is my first time ever checking the temperature of a radiator.

 

[Noobz347]

So, this could very well be normal operation and you're [looking] for issues to address?

If you're not throwing a code, press on with pride.


235* is within normal operating temp. Idle after heat-soak is when you [would] see it creep up. E-Fans don't move the same air as car moving, even at 30 MPH.

If anything (and I'm not saying that this is), I might do a radiator flush (if you didn't do it with the pump change), and spray some "Gunk" on the radiator fins and flush out with [low pressure] water from a garden hose.


Something else you can try just to ensure: Turn your A/C on while at idle and check to see that both fans turn on.

• Not that this matters, the radiator hose feels warm even when the CHT is above 220 F
• I took an infrared temp of the radiator after the car was running and the upper was showing 170F while the top right, bottom left, bottom right had a temp of 77F

Neither of these things mean anything.

The H and C is normal (which is weird because its a fake reading that's based off the high CHT)

It's based off of the Engine coolant temp sensor.

Motorcraft CX2409​

(Ford Part Number: DY-1149)

 

[wtfwork12]

So, this could very well be normal operation and you're [looking] for issues to address?

If you're not throwing a code, press on with pride.


235* is within normal operating temp. Idle after heat-soak is when you [would] see it creep up. E-Fans don't move the same air as car moving, even at 30 MPH.

If anything (and I'm not saying that this is), I might do a radiator flush (if you didn't do it with the pump change), and spray some "Gunk" on the radiator fins and flush out with [low pressure] water from a garden hose.


Something else you can try just to ensure: Turn your A/C on while at idle and check to see that both fans turn on.


Neither of these things mean anything.




It's based off of the Engine coolant temp sensor.

Motorcraft CX2409​

(Ford Part Number: DY-1149)

I dont believe the CHT being that high is normal, I've had this car for many years and it has never went past 216 F. 230 is getting up there and approaching the danger zone. The temp also never comes back down anymore when the fans go, so there is a big red flag there.

 

[Bullitt347]

If the CEL is not on, then it is not a problem.
If it is outside the parameters programmed into the ECU, then the CEL would come on.
The fact that the CEL is not on means that it is still considered "normal" despite previous observations.

 

[nickyb]

Call car shield and get some warranty on it ,then you can drive the outta it and if it melts down you get a new engine.

 

[Noobz347]

I dont believe the CHT being that high is normal

Yep, I got that part but do you have any data that suggests that it is not?

I've looked and cannot find it.

What was ambient temperature when you saw these elevated readings? Was it hot outside? Was the A/C running? We already know you were sitting at idle.

 

[FastDriver]

Fans didn't kick on in my all-aluminum Corvette, IIRC, until mid 220s... like maybe 226*.

240* seems a tad high to me, but I don't know better than the engineers, and it's not crazy out of range. I'd be worried if it were much above that, though.

 

[wtfwork12]

Gave up and brought it to Ford, tech said a CHT at 220-230 without going down can and will lead to a problem. Suspected there was a clog in cooling system somewhere, so I bought a new radiator and problem solved.