The F150 V8 engines (in general) tend to warm fairly quickly when operating normally. From right cold to full operating temp in about ten minutes city driving on really cold winter days.
If your Engine does not match this by a large margin then I am going to predict that thermostat is worn or weak and needs replacing.
1 take out the engine 2 put a new one in duhhhhhhhhhh
your heater will be cold, or your engine can over heat. your car can take a long time to heat up. Your inside heater will be cool, or your engine temp. will over heat.
The 2005 F150 5.4 L 3V engine takes 7 quarts with engine oil filter change , according to the Owner Guide
6 hours
6 qrts
4000# give or take depending on engine size
Most likely a defective thermostat.However,remember that there is a lot of metal in the engine block that has to heat up too.
First of all, the "block heater" is actually an oil or coolant warmer. It will heat the engine oil or engine coolant depending on location installed, and works similarly to an electric water heater. The rate and maximum temperature that the heating element reaches depends on manufacturer. Circulation of the fluid it heats also plays into how long it will take to warm the engine. In general, the larger the motor, the longer it will take to warm and the more power it will require to stay warm. A 7.3L engine will have a higher volume of coolant to heat where as a 5.9L engine.
8
With engine oil filter change ( 6 quarts / 5.7 liters of engine oil )
THERE IS NO GAUGE CHECK IT WHEN ITS COOL TAKE THE CAP OFF AND LOOK IN DO NOT DO THIS IF THE ENGINE IS WARM IT WILL SCALD YOU
6 quarts with filter change for the 4.2 L - V6 engine