No, it will not.
Yes.
As much as it takes. You could talking about anything from a Freightliner Sprinter up to a heavy haul truck.
Need to know what engine you have in order to answer this. In 2003, Freightliner had the option of Detroit, Cummins, Caterpillar, and Mercedes-Benz diesel engines.
You need to have it drained out.
11 gallons with filter
Depends on the engine in the Freightliner truck. Some require as little as 2 gallons, others require 11 gallons.
Whatever size the original purchaser ordered with it.
For Class 8 trucks, you could get either an 11.1 litre or 12.7 litre Detroit Diesel.
These come with an anti-siphon device built into the tanks, as most current production trucks do.
Principal Application: Mercedes MBE600 (2.7L) Turbo Diesel For Freightliner, Dodge Sprinter Vans
nope
The glow plugs are warming up prior to the motor being started up.