Cold air from heat as a result of air bubbles in coolant, specifically heater core. Bad design by Chevy means that air bubbles get trapped in heater core easily and are near impossible to get rid of. Also causes the "water rushing" sound heard in the dash when accelerating. In my case, the air bubbles were coming from a leaking head gasket. Coolant was burning off, constantly getting too low, and introducing air into the cooling system.
Had a heater core leak under dash in auto. Sweet antifreeze smell. Tried stop leak silver solution. Leak still present. Replaced heater core under dash. $$$...burped cooling system........trickle of heat at 2200 rpm's. Replaced thermostat. Burped again. Got temp up, purge tank half full. Still heat only at high RPM. Replaced water Pump(no change)
Brought into Chevrolet Dealership and had system flushed $$$.....Ran for a good week. No heat. Brought back to dealership. Dealership said lower intake Gasket leaking. Replaced gaskets all, and valve cover gaskets. Flushed again, purged air in system. Now over $2000.00 in repair attempts with parts. Only Chevy dealership in the interior of Alaska...-22 here today, and no heat in Wife's car..............Insane. Otherwise auto has been dependable.................
A D V E R T I S E M E N T S
Cold air from heat as a result of air bubbles in coolant, specifically heater core. Bad design by Chevy means that air bubbles get trapped in heater core easily and are near impossible to get rid of. Also causes the "water rushing" sound heard in the dash when accelerating. In my case, the air bubbles were coming from a leaking head gasket. Coolant was burning off, constantly getting too low, and introducing air into the cooling system.
- dredd, Chicago, US