Help my heater

My heater only works when the car is running. My husband said that it needs antifreeze, but to be honest, he can grow a great plant but knows nothing about cars. Please help!

I’m afraid that all car heaters work only when the car is running. It is a hot water heater, so it can blow hot air only when it has a continuous supply of hot water coming from the engine. When you shut off the engine, the water pump on the engine stops, so the heater can continue to blow hot air for only a few seconds until the cup or two of water in the heater core cools.

If you mean the heater only works when the car is in motion, but turns cold when the car is idling, like at a light, he may be right. Check the coolant reservoir under the hood. There should be markings to show the proper coolant level.

Also,the problem may be the thermostat. This device is supposed to maintain a certain temperature range of the coolant in the engine block. When they go bad, the tend to stick open and allow coolant to run through the radiator too quickly. This causes the coolant to run too cool during idle to maintain proper heat to the engine and to the car’s heater system.

So, did you look to see if it needs coolant?

What year Malibu and how many miles on it? There could be some blockage in your heater core that a good flushing could help. Or you could also have a water pump that needs replacing soon. Does the car get up to normal operating temperature?

Check coolant level first.

Most (if not all) conventional modern car heaters are a combination of a mini radiator and fan set-up. The hot water (engine coolant) which runs through the mini radiator is of course, heated by the engine . . . usually takes a few minutes to warm-up, and then you turn on the fan . . . which blows air through this mini radiator, turning the previously cold air warm, even hot. The effectiveness of this radiator could possibly be diminished by a lack of coolant. So check the coolant (do it when the engine is cold). Buy the 50/50 mix from an auto parts store, try it and post back. Rocketman