Car heater repair is one of the most common repairs we perform during the winter months. Customer complain of weak heat, no heat at all, or the vents blow cold. The heating system of your car is amazingly efficient and recycles engine heat back into your cabin to keep you warm during the cold New York winter months.
Engine coolant gets very hot as it draws heat away from your engine and dissipates the heat in the radiator. During the cold winter months this heat is reused to heat up the inside of your car. As part of the cooling system there is a tiny radiator called a heat exchanger inside your dash board that hot coolant flows through. Then a small fan disperses the heat out of the heat exchanger through the ducts in your dashboard then into your cabin. This is basic concept that all car heaters use to keep you warm in the winter months. That is why when you start your car in the morning you don’t get any heat until you warm up the engine.
As cars age and systems break down we will discuss the most 5 most common causes as to why the heater in your car might stop working in the winter months.
1. Thermostat that doesn’t close
Your coolant temperature is regulated by a thermostatic valve. When the car is cold the valve is closed and when the temperature increases to a pre-determined temperature between 180-220 degrees the thermostat opens to let coolant flow to the radiator to keep the temperature stable. The thermostat can fail in an open or closed position. If it fails in the closed position you will quickly notice as your engine will quickly overheat. When it fails in the open position then it will constantly let coolant go through the radiator and the engine will never get warm in the winter months. This will keep the coolant from getting hot enough to warm the cabin and you will get a weak heat or no heat at all.
2. Bad Dash Fan/ Blower Motor
Inside your dashboard there is a small fan that blows the hot air through the vents inside your cabin. This fan can fail and once it does it will not be able to transfer the heat from the heat exchanger to the ambient air inside the cabin. This repair can be very expensive depending on the model of car you have. On some late model cars the entire dashboard removal is required to get to the fan or the heat exchanger. On some cars the fan can be easily accessed and changed from under the dashboard.
3. Low Coolant
If you have a slow coolant leak then you might also experience a weak heater. As there won’t be enough coolant carrying heat energy from the engine to heat up the passenger cabin in your car. Adding coolant to the correct level will help solve this issue temporarily until the coolant leaks out again. The best way to fix this problem is to find the leak and replace the component that failed and leaked.
4. Bad bypass valve
Some cars have a bypass valve that prevents coolant from reaching the heat exchanger inside your dashboard until you turn the heat on. This bypass can also fail. If it fails in the closed position then your heat exchanger will never receive the hot coolant it needs to circulate heat inside the car. The bypass valve is usually not difficult to replace except in some luxury European models.
5. Clogged or Damaged Heater Core
As coolant deteriorates it tends to leave mineral deposits inside the cooling system. As most people neglect to get their coolant flushed every 5 to 7 years the deposits from the deteriorated coolant can clog various components. This includes the heat exchanger and other tubing leading up to the heat exchanger. We have also seen heat exchangers crack and leak from bad coolant. This can be an expensive repair as a coolant flush is not always enough to clear the clog. and if the heat exchanger is leaking then depending on the car the whole dash would have to come out.
These are the main causes we have seen when customers bring us their car because their heater isn’t working. Some of these repairs are inexpensive and can be completed in about an hour. Other repairs require the whole dashboard to come out and take hours to complete. That is why a proper diagnostic is important to know what is wrong as a misdiagnosis can cost you hundreds of dollars. If your heat isn’t working properly or your have any questions feel free to Contact Us with any questions.