how does a car heating system work?

[00 scrub]

I have been wondering how the heaters in cars work? I hear people talking about heater cores etc. Is there piping in the engine bay that picks up heat from the engine block and deliver it to the cabin? If that is how it's done, wouldn't it take a long time for the air to heat up enough to be substantially different from the incoming air? Also how does the temperature selection knob inside the cabin work? Is there some sort of airflow divider that divides incoming outside air with air coming from the heater (or heater tubing)?

[autxr]

The heater core is a small radiator and lives up in the dash area. There are coolant lines plumbed from the engine, so it is the antifreeze that is bringing the heat in. It flows through the radiator (heater core) and a fan blows accross it. Cold air in, hot air out.

The temperature knob adjusts the flow through the heater core, so you get hotter air by moving more hot liquid through the core.

Kind of a nice system until one of the fittings fails and dums coolant into the passenger compartment.

Scott

[00 scrub]

ok, that makes sense. Thanks for the explanation autoxr. I have one last question though, is the coolant/antifreeze so warm that it only takes a few seconds for the air to heat up to such a high temperature?

[autxr]

Yes, it is that warm.

Figure on a typical car it will be between 180 and 200 F. That is hot. on a cold day you would only need 70 deg. air to feel warmer. The heat exchange is pretty efficient, so it doesn't take long to heat the air up.

On really cold days, the engine will warm up faster with te heat off, and you will actually get hotter air (or cooler with the AC) if te fan is on low, but you will get less of it.

Scott