My 04 4.6 v8 over heated today sitting in traffic today. It hasn't over heated in awhile after I changed my thermostat. Today was a hot day and lots of driving. I do have electric fans and they do kick on...why else would my truck over heat?. Coolant if full. Of course once I started driving the temp needle went to normal. I'm unsure on what type of fans they are but still they kick on. I have a Bluetooth scanner to check my coolant temp driving...when should I worry?

 

It shouldn't overheat.

If you have E-fans, you need to make sure they're sufficient for the job, especially if you're going to be sitting in traffic.

It sounds like they're not pulling enough air through the radiator to do the job.

Another possibility is how clean are the fins on your core?

 

Temp sensor for the fans may not be kicking at the right temp...