I have a 2012 F150 5.0. I had my water pump and thermostat replaced recently. I've noticed if I'm driving for more then 20 minutes, the engine gets really loud. Like it goes to high mode. It never did this before I had this work done. Itll go back and forth from low to high like it's cooling down, but it's just really loud. Is something wrong? My temp gages haven't gone more then 1/2 way so far. Any recommendations?

 

It has been written that the needle on the gauge does not show true temperature. The PCM controls the needle and puts it in the middle of the ranger if the temperature is within a very wide specification. So your coolant temperature might be much higher than you think. The needle is basically just an idiot light analog, apparently. If you have electric fans they probably are actuated by a thermal switch or the PCM.

Might be that your new thermostat is stuck or the mechanic made a mistake. Why did you have them replaced anyway? Was there a problem with them?

 

The bearings in the pulley wheel were shot. It was rattling. I'm bring it back to the mechanic tomorrow to look at. He replaced the thermostat since he was in there.

 

Make sure he used a Motorcraft thermostat.

 

I'll have to ask him

 

Check the coolant level too. Low coolant can cause the fans to run high.