If you have a heater core leak yuo will not leak freon. You will leak antifreeze. If the a/c evaporator, which is the part in the dash that would be like the heater core exept when the air blows through it the vehicle cools down instead of warms up, is leaking then the freon will leak out if there is a hole in it. Depending on the size of the hole will depend on how quickly it leaks out. I have done several evaprator cores that took a couple of weeks to leak to the point where there was no cool air. According to my repair information yur blazer should have R134a in it. This is the newer refrigerant that is not supposed to hurt the ozone. The older refrigerant is supposed to hurt the ozone. If it is your heater core then age and heat has a lot to do with its lifespan. Also depending on what condition the antifreeze is will also have something to do with how long a heater core will last. If it is the evaporator you are talking about then age, pressure, and lubrication have a role in how long it could last. I have replaced heater cores and evaporators in vehicle that have had less than 50,000 miles on them and also have replaced original ones with over 100,000 miles on them. There is no way of determining how long one will last.
__________________
I hope this helps. Please click the Accept button to close the question.
