Suppose you are driving on a cold morning and turn on your car’s heater for warmth. At this stage, heater core needs hot engine coolant to warm the air inside your vehicle. Engineers install heater hoses in a car to make this possible. In this article, we will explain everything you need to know about heater hose and its role in vehicle performance.
What is Heater Hose?
A heater hose is a flexible pipe used to carry hot engine coolant between the engine and the heater core. It transfers heat from the engine cooling system to the vehicle’s cabin. So when hot coolant flows through the heater core, it warms the air inside your car. A heater hose mostly has a thick and flexible wall that can handle the demands of the engine compartment.
You can find these hoses in cars, trucks, buses and other vehicles that use liquid cooling systems. SAE J20R3 is an SAE standard that sets performance requirements for heater and coolant hoses used in car cooling systems. Hence, a heater hose that meets the SAE J20R3 standard is called an SAE J20R3 heater hose.
How Many Heater Hoses Are in a Car?
In most passenger cars, you will see two heater hoses. These include heater inlet hose (supply hose) and heater outlet hose (return hose). One tube transfers hot coolant from the engine to the heater core and the other carries the cooled coolant back to the engine.
Some vehicles can also use additional hoses for special heating or cooling systems. However, most vehicles use two tubes to complete the path that carries coolant through the heater system.
Where is the Heater Hose Located?
You can find heater hoses in your car’s engine compartment. They connect the engine or coolant system to the heater core. One end of this hose connects to the engine. The hoses pass through the firewall, which is the metal wall between the engine area and the inside of the car. The other end connects to the heater core, which is located behind the dashboard.
What Does a Heater Hose Do?
The basic purpose of a heater hose is to transport hot engine coolant to the heater core inside the dashboard. As the engine runs, it produces a lot of heat. The coolant absorbs this heat when it flows through the engine.
Some of this hot coolant travels through the heater hose to the heater core. A fan blows air over the hot heater core and warms the air before it enters the cabin. After that, the second heater hose carries the cooler coolant back to the engine where the cycle starts again.
Heater Hose Importance
A heater hose has an important role in your car’s heating and cooling system. It also maintains proper coolant flow and provides heat that helps clear fog and frost from the windshield. Moreover, this tube is responsible for maintaining the pressure in the closed cooling system.
This allows antifreeze to flow properly and supports the system to work effectively. If your car has a heater hose in good condition, you can prevent coolant loss. In contrast, a damaged or leaking hose can increase the risk of engine overheating.
Heater Hose Types Based on Shapes
Heater tubes are designed in different shapes, so you can fit them according to available space and connection points in a vehicle’s heating system. These are some common categories of heater hose shapes.
Molded Heater Hose
A molded heater hose has a pre-formed shape. It is designed to match the space and connection points in heating system of a car. Based on the vehicle’s design, they can have a simple curve, S shape, 90 degree bend or more complex angle.
Its construction allows it to maintain its shape during use. Therefore, you don’t need to install brackets or other external support.
Straight Heater Hose
This heater hose has a simple and straight design without built-in bends or curves. You need this type of tube to create a path between engine and heater core when the connection points line up in a straight route.
In fact, you can also cut it to the required length for different automobile applications. This way, straight heater hoses offer a simple and flexible solution for routing hot engine coolant through the heating system.
Dual-ID Heater Hose
A dual ID heater hose basically has two different inside diameters (ID) along its length. One end has a larger inner diameter and the other has a smaller inner diameter.
This design allows the hose to connect components with different connection sizes without additional adapters. Dual ID heater hoses provide a secure fit and maintain proper coolant flow through the heating system.
Note: ID means inside diameter, which is the distance across the inside of hose.
What Materials Are Used For Heater Hoses?
Heater hoses use materials that can handle high temperatures, coolant, pressure and engine movement. Manufacturers commonly use these materials to make heater hoses.
| Heater Hose Type | Material | Properties | Common Applications |
| EPDM rubber heater hose | EPDM synthetic rubber | Flexible, durable, coolant resistant and resistant to ozone | Passenger cars, trucks, SUVs, and general cooling systems |
| Silicone heater hose | Silicone rubber with polyester or nylon reinforcement | Highly durable, flexible and resistant to ozone plus coolant additives | Performance cars, heavy-duty vehicles, and demanding engine compartments |
| Polymer heater hose | Synthetic rubber or other polymer compounds | Flexible, affordable, easy to install and resistant to environmental factors | Passenger cars and light commercial vehicles |
| Fabric reinforced heater hose | Rubber or synthetic material with polyester or aramid fabric reinforcement | Flexible, strong, durable and suitable for routing through tight spaces | Passenger vehicle and commercial automobile |
Standard Heater Hose Sizes
- Most standard automotive heater hoses are available in ⅝ inch and ¾ inch inside diameters (ID).
- The 5/8 inch hose is common in passenger cars and works with many standard heater core connections.
- You can use 3/4 inch hose in larger vehicles, rear seat heaters or some special coolant connections.
- Smaller 1/2 inch hoses can serve bypass lines and smaller auxiliary connections.
- But 1-inch hoses are more common in heavy-duty trucks, buses & commercial vehicles with larger heating systems.
Bad Heater Hose Symptoms
A defective heater hose can cause problems with your car’s heating as well as cooling systems. In most cases, a damaged hose can reduce cabin heat and make it harder to clear fog or ice from the windows. It can also leak coolant and cause the engine to overheat. You should watch for these common signs to identify a faulty heater tube.
- Low coolant level
- Steam coming from under hood
- Engine temperature higher than normal
- Coolant smell under the hood
- Soft or spongy hose
- Slight or no heat from heater
- A crackling sound if you squeeze the hose while engine is cold
- Coolant leaking from heater tube
- Bulges, swelling, cracks, cuts or worn areas on hose
- A hose that collapses or looks damaged
How To Replace Heater Hose?
According to our experience, you can follow this method for an easy replacement of heater hoses.
Step 1: First of all, you should turn off your car and wait until the engine & coolant become completely cool.
Step 2: Now place a drain pan under the vehicle and drain the coolant from the cooling system.
Step 3: You need to loosen the hose clamps and carefully disconnect the old heater hose from the engine plus heater core.
Step 4: You must inspect the connection points for damage, corrosion or debris. It’s also recommended to clean them if needed.
Step 5: It’s time to connect the new heater hose to the engine and heater core in the same position as the old hose.
Step 6: After that, you can tighten the hose clamps to keep the connections secure and prevent leaks.
Step 7: Then, you can add the correct coolant to the cooling system according to vehicle manufacturer’s specifications.
Step 8: The final step is to check for leaks and coolant level. For this purpose, you need to start the engine and let it reach normal operating temperature. Then you should check the new hose and connections for coolant leaks.
Heater Hose Replacement Cost
Heater hoses face high temperatures inside the engine compartment. Hence, they can wear out over time due to heat and exposure to oil. Under normal conditions, a heater hose lasts around 80000 to 150000 km. So, how much does a heater hose cost? If you need to replace a heater hose, the average repair cost is approximately $150 to $250. But keep in mind, the exact price can vary based on the car’s make and model.
Heater Hose vs Radiator Hose Comparison
| Heater Hose | Radiator Hose |
| It feeds hot coolant to the heater core for cabin heating | It carries coolant between the engine and radiator for engine cooling |
| Generally has a smaller bore around 16 to 19 mm | Usually has a larger bore, approx. 25 to 45 mm or more |
| Carries a smaller amount of coolant | Transfers a larger volume of coolant |
| Has a longer and straighter shape | Has molded bends to fit the cooling system |
| Heater hose connects the engine to the heater core behind the dashboard | Radiator hose connects the engine to the radiator at the front of the vehicle |
FAQs
Is Heater Hose Same As Coolant Hose?
Yes, a heater hose is a type of coolant hose. But the two have different sizes and applications. Both hoses carry the same coolant, which contains a mixture of water and antifreeze. However, they serve different parts of the vehicle’s cooling system.
Can I Use a Heater Hose For Coolant?
Yes, you can use a heater hose for coolant, because a heater hose is designed to carry engine coolant between the engine and heater core. But you should use the correct hose type and size for your car.
What Happens if Heater Hose is Disconnected?
If you disconnect a heater hose, it can cause a sudden loss of cabin heat and coolant. It can lead to engine overheating if you continue driving. Moreover, hot coolant stops flowing through the heater core. So the cabin heater and defroster will only blow cold air.
Conclusion
If you are a wholesaler or B2B buyer and want to order custom heater hoses in bulk, you should choose the right automotive hose manufacturer. But this decision can be difficult because the market has many hose suppliers. Among them, RONTEIX is a trusted manufacturer of automobile and industrial hoses.
In our inventory, we have different sizes, shapes and materials of coolant hoses. You can also get OEM and ODM services for customized automotive hoses. Contact our team anytime to discuss your requirements.
