[Donbinnc]

I have a 1988 CK 1500 Silverado. I have an antifreeze smell in the cab and the obvious wet spot on the passenger side floor board. Also the defrost mode does not completely clear the windows. I found that the radiator coolant level is low and added almost a gallon of antifreeze/coolant.

Other than the obvious indicators I mentioned before I pretty sure the heater core has gone bad. Is there any other way to see if the heater core has gone bad?

If it is bad is it difficult to replace? Can anyone provide me replacement instructions or point me to instructions on the web?

Thanks.
Don