So this morning it was 6 degrees outside so I figured I would give my 88 DL more time to warm up. I went to get in the car some 20 minutes later and found to my surprise the heat was still blowing out cold air! I looked at the temp gauge and it was higher then normal. I hit the gas to drop the choke off and the temp came right down to normal. I checked hoses and all looked good so I drove the car about 25 miles. The car ran at normal operating temp but heat never got warm. It was working just last night. Could something have frozen? Any thoughts? My toes will thank you. IT IS COLD!!!

Do you hear a gurgling sound coming from the area by the heater core? It sounds to me like you have air in your cooling system. Removing it isn't too hard, though. It's best if you can park with the nose of the car uphill, the steeper the better. Remove the radiator cap, and squeeze the top radiator hose to burp the air out. Top off the coolant and repeat until you don't get any more air coming out. Start the car with the cap still off and check again to make sure there wasn't any air trapped in the sytem.I think this will take care of your problem.

come to think of it, no. I did not hear the normal gurgle. I am still hoping it has something to do with the ridiculously cold temp outside. How does the air just develope if it was working fine only 8 hours prior?