Radiator Fan Problem


New Member
Apr 26, 2017
I'm currently experiencing radiator problem with my v6 2013 mustang

I just changed coolant , relay slow speed side.

Engine oil temp and coolant temperature are fine except cylinder head temp

I've alway kept my eyes on cylinder head temp for about two years and it had always been 190-210, and while sitting in traffic it didn't go up at least stayed on the same temp

But now While on highway it stays up to 205 but when it sits in traffic cylinder temp goes up and the fan doesn't go off til cylinder temp reaches 232.

Once the fan goes off the temp goes down drastically from 232.

I noticed that coolant work well but the fan doesn't work properly, to test the fan i changed relay and turned on AC all the way but it goes off for 3 sec and shut off and repeat. Also the same while in traffic. It still goes up til 232.

Outside temp was even 60.

Does anyone know how to fix it?
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Active Member
Feb 28, 2017
Newark, OH
Not sure when the fan's supposed to go on, but it doesn't sound too major though different than what you're used to. I found the following online though this is just general. I'm sure someone else here with more experience can help you out.

Engine operating temperature
The normal operating temperature for a modern (e.g., 1996+) automobile engine, manufactured for sale or use in the US, will fall between 200 and 250 degrees F. Smog equipment and computerized combustion control favor a 'hotter' running engine. The proper amount and concentration of coolant in your engine will protect it.