As stated, it sounds like you are letting in as much cold air as you are hot air.
With the deluxe heater you can pull in outside air. The flapper valve is located at the top of the heater core just aft of the heater core itself. Make sure that the cable running to this flapper valve is connected, adjusted and working as it should. The cable connection is located on the passenger side of the heater assembly on the outside of the firewall, near the firewall.
As well this flapper has a foam rubber seal that can become deteriorated. This alone can cause cold air to leak past.
As 48bigtrucks says, you should have more than enough heat.
Last edited by Rusty64; 12/24/2010 7:29 PM.
