Sometimes when I go out to my truck and start it, I turn on the heater and the vents will blow a coolant smell for a few seconds.

Is this normal or is it something I should be looking into further?

 

You might check the heater hoses where they connect to the core,
make sure the clamps are tight and the hose ends arent checked.
The reason is that I had a core inlet with a solder blob on an old car once,Anti-freeze would squirt inside the a/c plenum.
Look at the evaporator drain hose or stick a q-tip in there to see if any coolant is visible.
Good Luck!

 

I also had the same problem,started to noitced when i had the heat on i could smell coolant.though it was kinda funny,because i just purchased the
truck 1 month ago and the guy had 3 smelly x-mas trees hangin from the mirror.had to replace the heater core,also installed a new evaporator while
i had the heater box on the bench.job took around 4-6hrs.

 

Almost certainly the heater core leaking.