3.5L 1997 Concorde, 106,000 miles.
I'm not getting any heat out of the heater.
It's somewhat intermittent. If the car is started up and the controls placed on heat, the engine temp gauge barely budges off the bottom mark, and heating air never gets warm. This is worst with the selector set for defrost. If the heat is turned off, the engine temp warms up to normal, about the middle mark on the gauge, at which point the heat can be turned on and cooks the passenger compartment quite nicely. I haven't had enough time to see if the engine temp drops after turning the heat on.
I've had it suggested that the heater core may be clogged, but I don't understand why a clogged heater core would prevent the engine coolant from heating up.
Any recommendations where to start with this issue?

Many thanks!

 

i would start with checking the level of your anti freeze. could have air pocket.i think theres a bleed on your intake manifold.moe

 

sounds like a thermostat

 

Much obliged!
The thermostat was most definitely the main problem--it had broken and I had to fish the pieces out of the manifold. (Thankful that they were LARGE pieces!!!)

One question on bleeding the system: As far as I could tell from the instructions, I was merely supposed to open the bleed valve and the coolant reservoir, attach a hose to the bleed valve to a container, and add coolant to the reservoir until the coolant began to run out the hose. It didn't work nearly so well for me.....I filled the reservoir.....and nothing happened. The level stayed the same, and neither air nor coolant came out the bleed hole. The bleeder was definitely open, as I could cause air motion in and out by squeezing the top hose. Eventually I gave up, turned on the motor, and let it run until the coolant heated up and forced air out the hole and began to spew warm coolant. What did I do wrong?
Thanks!