Category: Heater

Why Isn’t My Car Heater Working?

Why Isn’t My Car Heater Working? 

 

In many cases, problems with the heating system are problems with the engine’s cooling system. Therefore, most service work and diagnosis are done to the cooling system. In some cases, the heater core is the problem. In some vehicles, it is possible to make repairs to vacuum hoses and electrical connections without removing the heater assembly. If it is necessary to remove the heater assembly, the cooling system must be drained before removing the heater core. 

Heater Core

Why is my car heater not getting hot enough?

  • Air pockets in the heater core can interfere with proper coolant circulation. Air pockets form when the coolant level is low or when the cooling system is not properly filled after draining it. 
  • A gurgling noise in the heater core may be caused by a low coolant level in the cooling system. A low coolant level will allow too much air in the cooling system. The excessive air will mix with the coolant and create the gurgling noise. 
  • A restricted heater core will also cause a gurgling noise from the coolant passing through the restricted area. 
  • Coolant leaks. Internal engine coolant leakage is probable the worst-case scenario. 
  • The engine thermostat is staying open and the vehicle doesn’t reach operating temperature. 
  • Heater control valve malfunction. 
  • Blend door actuator motor malfunction. 

 

How do I fix the heater in my car? 

Problems that pertain specifically to the heater are few: the heater control valve and the heater core. Most often, if these two components are faulty, the engine’s cooling system will be negatively affected. Both items are replaced, rather than repaired

How to diagnose the cause of temperature control problems? 

When diagnosing a heating system that is inadequate, it is imperative that you follow a logical diagnostic routine: 

  • Make sure there is adequate coolant in the cooling system. 
  • Verify that the engine reaches normal operating temperature. 
  • Verify engine thermostat operation. 
  • Check if there is flow through the heater core. 
  • Check proper operation of the heater control valve. 
  • Check with a Scanner Blend Door Actuator Motor operation. 

 

How can I tell if my heater core is clogged? 

If the engine is reaching operating temperature and the heater output is not acceptable, the next step is to check to see that there is flow through the heater core. Some systems use a heater control valve .These valves may be controlled by vacuum, electricity, or a cable. Be sure that the valve changes position, allowing coolant into the heater core. If that area is good or not applicable, check the inlet and outlet temperatures or the heater hoses at the core. If one is cold, you have a restricted core. If both are hot and equal, you may have restricted fins on the outside of the core, or the blend door may not be opening to allow the blower to move air across the core. There will be some drop in outlet temperature if everything is working normally. Usually this would be 10-30 degrees. A drop more than that means the core is restricted.

How to diagnose window fogging problems in my car? 

A leaking heater core is often the cause of a windshield fogging problem. Windshield fogging is the result of hot and humid air that condenses on the cooler glass. 

A sticky film on the inside of the windshield may be caused by: 

  • A coolant leak in the heater core. 
  • Under this condition the coolant level in the radiator should be checked. 
  • A plugged air conditioning/heater case drain that allows water to collect in the case can become stagnant and produce a very pungent odor in the passenger compartment. 
Can you unclog a heater core? 

Heater cores are replaced, rather than repaired. Like the radiator, heater core tanks, tubes and fins can become clogged over time by rust, scale, and mineral deposits circulated by the coolant. Heater core failures are caused by leakage or clogging. Feel the heater inlet and outlet hoses while the engine is idling and warm with the heater temperature control on hot. If the hose downstream of the heater valve does not feel hot, the valve is not opening. 

If the heater core appears to be plugged, the inlet hose will feel hot up to the core, but the outlet hose will be cool.

How to try to unclog the heater core? 

flushing the heater core

Reverse flushing the core with a power flusher may open the blockage, but usually the core must be removed for cleaning or replacement. 

  • Check the inlet and outlet temperatures or the heater hoses at the core. If one is cold, you have a restricted core. If both are hot and equal, you may have restricted fins on the outside of the core, or the blend door may not be opening to allow the blower to move air across the core. 
  • There will be some drop in outlet temperature if everything is working normally. Usually this would be 10-30 degrees. A drop more than that means the core is restricted 

 

Cleaning a clogged evaporator/heater case drain tube often eliminates a windshield fogging problem. If the drain is clogged, a leaking heater core will allow engine coolant to accumulate in the housing. A clogged drain also allows condensed water vapor to accumulate. Both problems add moisture to the air, which tends to fog the windshield. 

What is the average cost to replace a heater core?

The average cost for heater core replacement is between $580.00 and $980.00. Labor cost will depend on the make, model, and year of the vehicle. In most cases the entire removal of the dashboard is necessary to gain access to the heater core. 

How many hours does it take to replace a heater core? 

2015 BMW 320i Sedan (F30) L4-2.0L Turbo (N20) 

The Heater core replacement labor time in this vehicle is 9.1 hrs. 

 

 

-2013 Toyota Corolla L4-1.8L  

The Heater Core replacement labor time in this vehicle is 5.2 hrs. 

 

-2010 Ford Truck F 150 2WD V8-4.6L

The Heater Core replacement labor time in this vehicle is 5.9 hrs.

 

-2010 Volkswagen Jetta Sedan (1K2) L4-2.0L DSL Turbo

The Heater Core Replacement labor time in this vehicle is 2.8 hrs. 

 

A/C thermal expansion valve.

Normal auto A/C vent temperature

Higher than normal auto a/c vent temperature.

Heater control valve malfunction

When the A/C is in operation, the duct outlet temperature is higher than normal on a vehicle equipped with a normally closed vacuum heater control valve.

Heater control valve stuck-open.

A stuck-open heater control valve would allow the heater core to add heat to the cooled air reducing the effectiveness of the a/c system.

With a normally closed heater control valve, vacuum would be applied to the valve to cause it to open and add heated air.

Vacuum would not be applied to the valve in A/C mode so a vacuum leak would not cause this problem.

Heater control valve stuck-closed.

A stuck-closed valve would restrict coolant flow to the heater core and the complaint would be no heat.