Heater Hose


Heater Hose

Heater hoses are used to transфport hot coolant to the heater core and to return cooler coolant back to the engine. They are crucial for both engine cooling and climate control systems, helping for preventing engine from overheating, while keeping your passengers warm in winter. 


A set of heater core hoses usually consists of one inlet hose and one outlet hose. The first one delivers hot coolant from the engine to the heater core, so the heat from the coolant can release into the air that passes through the core from either inside or outside the vehicle. Then this hot air is used to protect your windows from frost and condensation as well as to keep your passengers warm in cold weather conditions. The cooler coolant is then returned to the engine via the outlet hose. Since the heater core allows for reducing coolant temperature it can be considered as an additional radiator, helping for keeping the engine running within the normal temperature range. Besides, made from flexible rubber, heater hoses absorb vibrations caused by minor engine movements, which prevents their damage and allows for proper coolant circulation. 

Cracked or damaged heater hoses can become a source of a variety of engine cooling and climate control systems problems, which is why they must be properly maintained and replaced if necessary. As a part of your cooling system, a leaking heater core can lead to a significant loss of coolant, resulting in poor engine cooling and overheating. On the other hand, a lack of coolant will keep your climate control system from supplying heat to your passengers and window glasses. 

Whichever the consequences of a bad heater hose appear, none of them are desirable. To avoid such an experience, we recommend you to pay attention to the most common warning signs of a bad heater core:

  • You notice a sweet smell or stream coming from under the hood
  • Little or no heat from the vents
  • Lack of coolant in the system 
  • Drops of coolant under the vehicle or a leaking hose
  • Your temperature gauge shows engine overheating 
  • Cracks or any other damage to heater hoses
  • Your heater hoses are soft or spongy to the touch
  • Crackling noises from the hoses in cold weather conditions

Heater hose troubleshooting and replacement 

Since a leaking heater hose can lead to a low coolant level and, therefore, engine overheating, it is a serious issue which must be addressed as soon as possible to prevent damage to the engine. Once you notice any warning sign of a bad heater hose, ask you mechanic to inspect the climate control and cooling systems for damage and wear. A bad heater hose can be just one of existing problems.

The mechanic should check all parts and components related to heater core operation. If he or she detects any other faulty parts they must be replaced together with a bad hose to restore the functionality of your climate control and engine cooling systems. This will keep you from unplanned repairs in the nearest future and save lots of headache.

Unless you’re a professional mechanic, we do not recommend you to deal with climate and cooling systems yourself. While replacing a hose seems to be an easy and simple task, draining, flushing and bleeding the system can be tricky if you don’t have the right equipment and experience. Leave this job to a professional, who will take care of everything and check the functionality of both climate control and cooling systems when the fix is done.