My truck seems to be running fine, but I have to top off the coolant reservoir constantly. There is always a little bit of dirty coolant in the bottom, and I can see some when I remove the radiator cap as well. I was going to flush the whole thing this weekend. Any idea where my leak might be? My first thought is the hose that leaves my reservoir.

It's a 2010 F150 XLT 4.6L

 

I would pressure test the system to see if it holds pressure while you examine for leaks. I would look very closely at hose connections and the weep hole on the water pump for leaks.

 

I'd recommend checking the hose for any visible cracks or signs of wear. Also, inspect the clamps to ensure they're snug. And take a good look at the radiator too. Sometimes, you can spot small leaks near the seams or connections. Just something to keep in mind when you're doing your flush.