After doing a bit of a search I believe the Normal operating temps for a 2006 5.4l is around 190F.

I have had my edge now for over a year and my engine coolant temps run from 170-180F In the winter here when the temps are below 30F I see usually around 165-170.

It will spike to 185 when it is first warming up, I am assuming right before the stat opens up. Then drops down to even the 150s then level back out around 165-170.

What I am curious is should I replace my thermostat? My MPGs have been fine. I have an edge CTS on the 3rd setting and even in the winter intown I get 15-16MPG. Just took the truck on a 450mile drive and got 16.7MPG. That is calculated by had. Temps outside were 35 on the way there and 19F on the way back with a 15MPH head wind. Driving speed was 74MPH.

That is with sand bags and warming up when needed, when taking my wife and boys out in the truck.

The only thing that bothers me is the heater feels weak. I do notice when I get up to close to the 180's my heater works much better!

Thoughts?

 

I would replace thermostat. That's too low of an operating temp. Should be 190 to 200 depending on weather. 150 is way too low. I swear my heater could bake a ham, it does take a little bit to warm up, but we've got a good size radiator.

 

I have a 2006 Lariat and my water temp is right around 185 degrees. I second the idea about changing out your thermostat. I believe it's a piece of cake to reach.

 

While running mine will settle into 185 to 195 on the highway at the temperatures you are driving in. I suspect your thermostat is fine. While stopped my heater also has a much reduced output, but that is because the flow through the heater core is much less at idle than at highway speeds. You are blowing 19F air through a 10"x10" (guessing here) radiator that has very little water flow through it at idle. If it heats up nicely at higher RPMs or when you change to recirculated air, it is probably as good as it will get.

 

Thanks for the input fella's. I figured it was a bit low. It does look like the thermostat is a breeze to get to. I will just go to ford and get theirs. I have had some bad luck in the past with some aftermarket ones. Last night I took it out on a 45 min drive with my boys to run some errands. Temps outside were 20F. My truck ran 176-180F.

 

just order one from tasca parts I got one for like $7 and its motorcraft.

 

Ordered a motor craft one from eBay. Tasca was 15 after shipping. And the gasket was another 7.

Including the gasket. Ebay was 18

 

Yep, 186 is what mine levels off to

 

72 degrees on my way home today here in beautiful San Diego, i was in between 185-190 my whole way home

 

My 06 5.4 runs from 190-195 most of the time. Even with the sub-zero temps in this winter its doesn't drop below 190. Yes, my heater will cook a turkey when it warms up, can't put it more than half way on the temp or I'll get cooked out of the truck. The highest it ever went is when I was towing my travel trailer up a 10,000 ft mtn in the summer with A/C on-went to about 215 and then came back down after I got to the top to 195.