A car's heater does not generate heat if the coolant level is low or restricted by buildup, if the water pump failed or if the thermostat is broken. The heater fan is also sometimes an issue.Know More
According to the Popular Mechanics website, a common cause of a car's heater not working is a buildup in the heater core. Grime or other sediment accumulate in the core and restrict the flow of heated coolant that serves as the source for the heater. The coolant needs to be flushed and replaced. This problem also occurs if the coolant is low, in which case it needs to be topped off.
Another possible problem is the thermostat. The thermostat controls a thermal valve that opens when the engine gets hot and closes when it gets cold. If the thermostat is worn out or broken, the thermal valve might remain open, which does not allow the coolant to warm up enough to provide heat for the heater. The thermostat then needs replacing. This problem also occurs if the water pump fails, in which case the car also overheats.
If the heater core is functioning properly but only a trickle of heat is coming from the vents, the problem might be the heater fan. Either the fuses for the fan or the whole fan might need replacing.Learn more about Car Parts & Maintenance
There are various possible reasons why a car makes a humming or whirring noise as these sounds could be a sign of a bad bearing in the steering system, water pump or alternator. Faulty air conditioning systems may make a similar noise as well, especially if there is a problem with the serpentine belt, which can get stretched and worn out. The tensioner may malfunction as well and defective air conditioners usually have more of a buzzing noise, particularly when the system is overcharged or when liquid refrigerant enters the compressor.Full Answer >
A car owner will know if the car's water pump is leaking if the cooling system constantly loses coolant. Another indication of a leaky water pump is an overheating engine.Full Answer >
Coolant leaks and engine overheating are usually caused by a failing water pump. Automotive water pumps are designed to leak coolant through weep ports as a warning that they are failing. Aside from overheating, a distinctive grinding or whining noise caused by a bad bearing is also a symptom of a bad pump.Full Answer >
The purpose of a car water pump is to push coolant through the car's engine block, radiator and hoses to get the engine heat away from the system. Most frequently, the water pump drives off the crankshaft pulley or the crankshaft itself. The coolant that gathers between the impeller blades travels outward using centrifugal force, and suction draws the coolant into the water pump from the radiator.Full Answer >