Pull the blower motor out and check both the motor, the blower wheel and the housing for any trash that may be stuck in it................
possible clogged or damaged heater core
The belt has worn on the edges and creates friction which causes squealing. Also, sometimes when a belt is cold it will squeal.
The heater might blow cold air in a 2000 Silverado because the thermostat is sticking and not changing from cold to heat. The thermostat is usually located in a hose that leads from the radiator to the motor.
The heater may not be on - but the fan still blows air through the vents when they're open !
Check piping. Make sure cold line going into cold side of water heater and hot side coming out hot side. Cold feed for water heater should come off main cold line. Make sure valves are open to and from water heater.
You may need to add water to your cooling system.
It is probably your thermostat. That will make cold air come in. It's probably stuck open. The part is only about $4.00 at Auto zone.
Heater core (radiator) needs to be cleaned or changed
My central heater will not come on while the pilot is lit,The heat does not kick on.
no.....the heater would have to be leaking
You will get some back pressure from the water heater. It will come out of either the hot or cold. Shut the tank off if there is a shut off there.
Depending on how old Ur heater is and what type of plumbing u got normality rust a reddish color comes from Ur heater u also get it from old iron pipe