Occasional whiff of coolant smell inside cab

From inside my 2011 Tacoma 4.0 (120,000 miles / 192,000 km) I get the occasional whiff of coolant.
I suppose I'll need to pay more attention to other conditions like weather conditions, temperature, driving patters, etc to see if there's some sort of pattern, but it really is only occasionally I encounter this.
I had the coolant changed at the dealer a year ago, and just checked the level, and it's right at the top.
Is there any way to know if it is a drip, if it's coming from inside the cabin?

Also, not sure if this is related but also occasionally when I turn on the heater blower, there's a completely different smell I get hit with... it's hard to describe, but it's an industrial smell, not quite like oil, and not sweet like coolant.

 

Other than doing a pressure test, there isn’t an “easy” way.
The heater core is in the center of the dash below the radio.
You can remove the lower console, or pull the carpet back and feel for wet spots.

I can’t say I’ve smelt coolant inside the truck.
I get the occasional coolant smell from outside my truck. Kind of concerned me the first time I smelt it.
Never a problem yet in 11 years of owning it. Coolant stays full.

The only smell I get inside the truck is the notorious “mildew” type smell, that all Toyotas seem to get if park outside full time in humid climates. Running the A/C with Fresh air OFF seems to help some.
In the winter months, the smell goes away.

 

Do the evaporator clean and clean the ducts, there's at least one good thread on it and it doesn't take long.