2000 Chevy Malibu Heat

Hi:
When you say the heat only comes on for 2 seconds, do you mean the blower motor? Also, how hi does the temp gauge get? Do you hear the cooling fans come on?

If the fans come on, then it could be a thermostat. However, the radiator may be plugged or a rad hose could be collapsing. WHen the temp goes up, make sure the upper and lower hoses don't collapse. If they are fine, the easiest thing to try is the thermostat. If that still doesn't work, look toward the radiator. ALso, to check your old t-stat, place it in a pot of boiling water and see if it opens.

As far as the heater, let me know if it's the motor that only works a few seconds or there is no heat coming from the core.

Joe