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

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

 

Possibly.
Disconnect both radiator hoses and try flushing the radiator with a garden hose until you get clear water coming out of the bottom.
Then stick a thick bung into the lower outlet to close it off and pour some diluted clear vinegar into the radiator until it's full. Leave for 24 hours before flushing the radiator again with a garden hose, reconnect both hoses, refill with coolant, start the engine and let it idle with the heater on MAX and the cap off the overflow reservoir until the bubbles stop. Top up the reservoir as required and then go for a minimum 10 minute drive.
Let the engine cool down again for at least 4 hours, recheck the coolant level in the reservoir, and top up if necessary.