Anti-freeze depletion / funny smell

I am the owner of a 1994 Cadillac Sedan de Deville. 4.9 liter V8 PFI

Lately I have this problem that my engine coolant is always low. After the car gets hot it smells as though there is electrical burning in the car but I cannot find any source of electrical burning and no melted wiring.

However just about every time I drive it the reservoir loses anything I have added and is bone dry. Now a couple of things:

1.) The oil is not frothy so i don't believe I have a head gasket issue.
2.) The car doesn't overheat although its around town usage.
3.) I find no leaks of coolant on the floor in the garage whether parked or parked after a long drive.

But I keep having to add antifreeze.

Could the smell be related and what should I be looking for?
The radiator system has not been flushed in the 4 years since I have owned it.

What should i be looking for?
What could my problem be?