Will flushing or backflushing solve heater core clogging? on 1995 Chevrolet Monte Carlo

heater is still working and I haven't noticed liquid in carpet,although I did see whisps of vapor coming from dash.I'm going to replace waterpump and thermostat .I will change heater core if all else fails.So how likely is heater core flush to solve overheating?

Asked by for the 1995 Chevrolet Monte Carlo