'03 Buick Century heater/defroster

[DC84]

I'm having trouble with my heater and windshield defroster. They both will eventually heat but only if my car is being driven. For example, if I'm on the expressway, they work fine. If I am in stop and go traffic they will cool down when I'm idle. Forget trying to defrost my car in the morning. It never heats up. My rear window defogger works fine. Any suggestions?

[012620]

My son was having the same problem with his 2000 Century. He was one or two quarts low on antifreeze. After he added more antifreeze the problem was temporary resolved. Could be a leaking UIM gasket.

[richtazz]

I agree with 012620. Check your coolant level. Filling the cooling system will help the symptom (lack of heat) but not the true problem.

The 3.1 engine is known for it's bad OEM gaskets that allow coolant to leak into the lifter valley and diluting the oil. Check your oil and oil level. If the oil is overfull and/or cloudy, you need to get the lower intake gaskets replaced before you overheat the car due to the low coolant issue, or wash the bearings out due to the coolant getting in the oil.