I drive a 04 f150 5.4 3 valve and I noticed this since I got the truck that when it gets colder out I get white sludge under the oil cap from condensation. I put a new thermostat in the truck and it runs at 190-195 and my average drive to work is 22 miles each way. I run ams oil synthetic oil and change it every 5k. Is this normal for these trucks?

 

Clean it off, you're fine.

 

It is condensation produced from inside the engine. Check all filters to make sure they are good (including the PCV)