Any reason why only recently my car heater even when on the cold position produces warm air. It then goes cold but occasionally goes warm again even on the coldest setting before going cold again.

Any reason why only recently my car heater even when on the cold position produces warm air. It then goes cold but occasionally goes warm again even on the coldest setting before going cold again.

I would check your coolant also check your oil cap make sure there is no white slush i.e head gasket trouble....is the heat of the engine high on the gauge? .