If you open your car’s hood, you can see several types of hoses around the engine bay. Among them, heater hoses and coolant hoses are two common types. But most car owners and mechanics get confused about these vehicle hoses. So today, we will compare heater hose & coolant hoses and highlight points that make them different from each other.
What is a Heater Hose?
A heater hose is a flexible rubber or silicone hose that transfers hot engine coolant to your car’s heater core. You will see this heater core located inside the cabin. It uses hot coolant to produce heat. If you turn on the heater, then coolant will flow through the heater pipe to the heater core. This will warm the air before it enters your car’s cabin.
How Many Heater Hoses Are in a Car?
In most motor vehicles, you will find two heater hoses. They are present near the back of the engine.
- Inlet heater hose: This tube carries heated fluid between engine/water pump and heater core. If engine warms up, the coolant will pick up heat and flow through this hose. The cabin heater unit then uses this high temperature to keep the inside of your car comfortable.
- Outlet heater hose: Engineers install this flexible pipe to transport cooler coolant from heater core back to cooling system. It basically provides a return path for coolant after it travels through heater core.
What is a Coolant Hose?
Coolant hoses are main pathways of a vehicle’s cooling system. They carry a large amount of hot coolant between different parts of your car’s cooling system. These include engine, radiator, coolant reservoir and other cooling setup components. The most popular materials for coolant tubes are silicone rubber, EPDM rubber and reinforced rubber.
How Many Coolant Hoses Does a Car Have?
There are mainly two types of coolant hoses in most basic passenger cars. Heater hose is actually the sub type of coolant hose. We told you about these tubes in the above section. Apart from this, below is the second main category of engine coolant pipes.
Radiator hoses: These large pipes connect engine and radiator. Their main job is to keep the engine at a safe temperature. Radiator hoses are further classified into two types:
- Upper radiator hose
- Lower radiator hose
Note: There is no fixed number of coolant hoses in every vehicle. The exact count depends on your vehicle’s make, model, engine and cooling system design. For example: you will notice 4 to 5 coolant tubes in old model vehicles. However, modern or complex vehicles have a cooling setup with 10 to more than 20 coolant hoses.
Difference Between Heater Hose & Coolant Hose
Heater hoses and coolant hoses both carry engine coolant, but they serve different parts of your car. This table will show you the main comparison between these two automobile hoses.
| Aspects | Heater Hose | Coolant Hose |
| Function | They carry hot coolant to and from heater core for cabin heating | Transfers antifreeze mixture through main engine cooling system |
| Coolant volume | Smaller amount of cooling fluid | Large amount of engine cooling fluid |
| Dimensions/inner diameter | 16 to 19 mm (5/8 – 3/4 inch) | 25 to 45 mm or more |
| Shape | Straight or pre-molded | Straight, T-shaped, curved & elbow designs |
| Silicone upgrade | Improves heat resistance and heater-circuit durability | Promote cooling system performance and reliability |
| Popular purchase options | Straight lengths by the metre | Molded hoses or vehicle hose kits |
| Location | Near rear or side of the engine bay (leading toward cabin) | Around front or side of engine bay (near engine and radiator) |
| Price | Generally lower and cheaper | Higher rates for molded pipes and complete kits |
Function
The primary job of heater hoses is to deliver hot engine coolant to the cabin heater matrix. Then the heater core will utilize this coolant’s warmth to provide heat for your car’s cabin.
On the other hand, you need coolant hoses in your vehicle to transfer coolant through the main engine cooling system. This flow removes excess engine heat and keeps the overall system at normal temperature.
Coolant Volume
Heater Hose Cooling Fluid Volume: Heating system hoses carry a small amount of engine cooling fluid. The reason is that their function is only to feed the cabin heater core. The total coolant holding capacity of two pipes is 0.25 to 0.5 quarts (0.25-0.5 liters). But if we combine the heater core and hoses, then the total amount will be 1 to 2 quarts (0.95 to 1.9 liters).
Coolant Hose Total Coolant Capacity: In contrast, these flexible tubes are designed to transport a large amount of engine antifreeze mixture. In most cases, they can hold approximately 0.5 to 2+ quarts (0.5 to 2 liters) of coolant.
Bore Size
- Heater Hose Sizes: The bore size is actually the inner diameter of the tube. Heater hoses have a small inside diameter (ID). Most common sizes are 5/8 inch (16 mm) and 3/4 inch (19 mm).
- Coolant Hose Sizes: Main coolant pipes such as radiator hoses have a large bore. You will generally find these tubes with an inner diameter of 25 to 45 mm or more.
Helpful: Can you replace a coolant hose with a generic hose of the same diameter?
Hose Shape
Heater tubes are available in two main forms: straight and pre-molded hoses. We advise you to choose only a straight tube if you see enough open space and the conduit can be fit without sharp bends. Otherwise, you can use a pre-molded tube if you need to install it around tight spaces or a firewall.
There are multiple shapes of coolant hose present in the market. For example, you will find some tubes with custom bends. But other coolant pipes have simple designs like 45° or 90° elbows, straight sections and T-shaped hoses.
Connection Points / Location
Heater Hose Location: You will notice vehicle heater hoses near the rear or side of the engine bay. They go toward the vehicle’s cabin (inside dashboard) and connect to the heater core.
Coolant Hose Location: If we locate main coolant hoses, you will commonly find them around the front or side of the engine bay (near engine and radiator). You can install an upper hose to connect the radiator to the engine. And a lower pipe links the radiator to the water pump. Keep in mind, their exact position varies based on vehicle design.
Common Purchase Type
Heater hose buying options: Most car owners buy heater hoses in straight length/section by meter. After that, you can obviously cut the pipe to the length you need, so you can fit it into the heater system.
Coolant hose purchase option: In case of coolant hoses, they are commonly sold in the form of molded hoses or vehicle hose kits. That means, you do not need to bend it yourself. Further, the kit includes several hoses made for the same vehicle. Hence, you can order the complete set instead of buying each line separately.
Silicone Upgradation
- Engineers replace standard rubber heater hoses with silicone hoses to improve heater circuit durability. It also offers better resistance to the heat from hot engine coolant. Hence, silicone heater hoses can stay flexible for longer.
- If we talk about silicone upgrading of coolant hoses, then the main focus is on cooling system durability and reliability. Plus, this change will reduce the chance of flexible tube failure during harsh driving conditions.
Cost
This table will show you the heater hose cost based on the option you choose.
| Item | Heater Hose Estimated Cost Range |
| Heater hose price (pre-formed generic tube) | $15 to $35 per piece |
| Bulk cut-to-fit heater hose | 2 to 5 US dollars per foot |
| Heater hose replacement cost (labor fee) | 100 to 200 USD |
| Molded OEM | $30 to $85+ per piece |
Below is the price breakdown for coolant hoses.
| Category | Market Price of Coolant Hoses |
| Coolant hose price | $15 to $40 for basic upper or lower radiator hoses |
| Coolant hose replacement cost | 300 to more than 600 US dollars |
| Full hose kit | $40 to $250+ |
Bad Heater Hose Symptoms
Heater hoses can become defective for multiple reasons. Common causes are extremely hot coolant, physical rubbing, high pressure or poor installation. As a result, faulty heater hoses lead to several problems and show these symptoms.
- Coolant leakage under your car
- Low engine cooling fluid level
- Sweet smell inside vehicle
- Weak or no heat from heater
- Engine overheating
- Soft, swollen or cracked pipe body
- Bulges or visible damage on hose
- Coolant dripping around tube connections
- Steam or smoke from engine bay
- Frequent need to add coolant
Bad Coolant Hose Symptoms
For coolant hoses, high engine temperature, wrong coolant or damaged clamps are big red flags that can damage these tubes. Nonfunctional coolant hoses can lead to following issues in your vehicle system.
- Coolant leakage near radiator/engine
- Low cooling liquid level in reservoir
- Engine overheating
- Cracks or splits in hose
- Swollen or collapsed hose
- Hard or brittle conduit surface
- Coolant puddles under front of your vehicle
- Steam from engine bay
- Coolant warning light turns on
To Sum Up
RONTEIX is a professional manufacturer of premium quality industrial hoses and automotive hoses. We supply hoses for automobile, food grade, marine, pharmaceutical and mining industries. Silicone coolant hoses are popular choices among our customers.
Our R&D team can also customize hoses in a wide range of sizes and materials according to your requirements. In fact, our flexible MOQ also allows you to start with small quantities. So if you have inquiries or want to buy car hose at factory price, you can contact us today.
Frequently Asked Questions
Is heater hose the same as radiator hose?
No, a heater tube is not the same as a radiator hose. Both tubes carry engine cooling liquid, but they have different sizes & jobs. A radiator hose is larger and handles the main coolant flow. The heater pipe is smaller and carries hot coolant only to and from the heater core.
Can I use heater hose for coolant?
We never recommend you to use a heater tube as replacement for other coolant hoses. Because their primary job is to make connections between the engine and heater core. So, they are not able to handle a larger coolant flow through different engine parts.
Are silicone radiator hoses better than rubber?
Silicone radiator hoses can handle temperatures around 350°F to 500°F. They can last for many years as well. Traditional EPDM rubber hoses cost less but have a shorter service life. Hence, silicone hoses are your good choice for high-performance or racing vehicles.
Can heater hose cause overheating?
Yes, a faulty heater hose can cause your car to overheat. This pipe is part of the engine’s pressurized cooling system. If this tube cracks or leaks, then your vehicle can lose coolant. Low coolant levels can reduce cooling performance plus lead to high engine temperature.
Can you use heater hose as a coolant hose for radiator?
No, you should never use a standard heater pipe as a permanent replacement for a radiator hose. As you know, heater hoses have a small diameter. But radiator hoses are much larger. If you use the wrong hose, it will restrict coolant flow and will not fit the radiator properly.
