Heater Problems

[hamel01]

We have a 1991 Buick LeSabre that is having heating problems. It blows warm air but not much of it. I shot the engine with an infread gun and the line that comes out at the thermostat is around 170 after about 20 minutes of running. The heater is on high in the car with it on defrost but it takes around 20 minutes of driving to get the windows completely defrosted and around 40 min untill you are starting to feel somewhat warm in the car. My question is how do i go about getting to the heater core to look at it? Is it through the hood or in front of the passenger seat? What type of problems might i run into? Oh yeah and the cooling system was fluched last spring and the thermostat has been changed twice. Thanks for your input.

[93LaSabreH3]

Are you sure your radiator is topped off? Have you checked since trying to use the heater? Reason I ask, you are describing a classic situation where there is an air lock in the system. Air lock is trapped air, in your case the heater core. Sqeeze the hoses, do you feel water moving? IF not you will need to purge the air.

IF your radiator is full while running.

Try this. Get the engine up to normal operating tempurature. Feel the rubber lines going to and from the heater core. Be aware of moving parts and avoid them. Both heater core lines should be warm.
IF only one is warm you have a blockage somewhere. Try flushing just the heater core.
IF both are warm, the problem lies elsewhere. Maybe a vent is stuck closed preventing the air from circulating around the heater core.