My heat won't stay on.

Gingermain

Hi I have a 2000 durango 4x4 my heat will work some days for a little while or all day,and other days it just doesn't work. When it does work out blows good hot air, but when it doesn't it's just cold. Please help winter is about to get bad and cold and I need heat

Mr_Shiftright

Some possibilities might be a sticking thermostat; or air trapped in the cooling system (did anyone change or add coolant recently?), or being too low on coolant, or a really clogged up heater core. With vehicles this old there are a lot of possibilities related to age, maintenance, etc.

Short answer--it's a circulation problem of some sort.