I have a 95 blazer 92000 miles. I just had the antifreeze, thermostat, hoses, changed and system flushed out. Sometimes when I drive I get an odor of antifreeze when heat or vent is on. It dosent happen all the time. The passenger floor is dry. Could it be a bad heater core even though its not leeking? Also one other time when I was driving there was a crackling coming from under the dash then it stopped and then there was a strong smell of anti freeze.

You will get a smell for a bit when you have all those things done.

Air out the cabin and if it is still happeneing after a month, you will have to replace your heater core.

I changed the heater core and it took approx 7 hrs. what a pain in the ass. At least the smell is gone