[Shotimes] anti freeze smell

[rschirmer22@cox.net]

Guys

I have a '93 ATX with less than 150,000 miles. However, on occassion I get a whiff of antifreeze smell inside the car; even though my antifreeze level does not drop much. 

hate to ask, BUT am I getting ready to lose my heater core??? can I pressure test the cooling system and find out if this is the problem?? And I also have heard rumors that this replacement is a beast, but how involved is this heater core replacement? I do have the big Helms manual, but does anybody have any instructions that can help out on this possible "test of will"??? I don't see any posted on the shotimes topics??
 Thanks
Bob