Vacuum Hose On A Car: What Should You Know About It?

The vacuum hose on a car can look like a normal tube, but its role is much more. It becomes a special connection between automotive accessories and components.

Any gas-powered engine should have a couple of these flexible tubes. You may also look for them in diesel automobiles.

But a tiny leak in your car’s vacuum hoses may affect the engine’s operation and performance. Therefore, you should be well-informed about these tubes for car repairs.

Keep reading the article below to learn more about car vacuum hoses.

What Is A Vacuum Hose On Cars?

vacuum hose on a car
A Vacuum Hose

It is similar to a car’s vein system connecting the vehicle’s accessories and components to the engine’s vacuum. Their other name is “vacuum tubes” or “vacuum lines”.

A gas car typically has 5-6 tubes around the engine. Yet, some older vehicles have 12 or more tubes. Most are rubber and go with components and hose clamps for locking.

Their thickness and size depend on their function.

Vacuum Hose On A Car: Everything To Know 

Vacuum hoses on cars streamline your control over some vehicle components such as wiper PCV valves, vacuum brake boosters, EGR valves, vacuum regulation, HVAC controls, heater control valves, and more.

What Does Car Vacuum Hose Work?

They make your car easier and safer to control vacuum-powered car parts (no less than six components).

These components include power steering, windshield wipers, heater valves, brake boosters, EGR valves, vacuum regulation, HVAC controls, PCVs, and many other valves.

Where Is Vacuum Hose In Car?

It may depend on the automotive hose and model, but it is between the intake system and the brake booster.

What Are Vacuum Hose Car Types?

Not all vacuum hoses are the same because they include different types.

The main three types of vacuum hoses are PVC-based, silicon-based, and rubber-based, depending on the structural material.

Also, engine vacuum hoses may be classified into two categories based on the pressure they may handle.

How Many Sizes Does A Vacuum Hose Car Have?

Vacuum hoses have a typical size from 3/16-inch inside diameter (ID) to 5/8-inch inside diameter (ID).

All these lines can work the same but come in various sizes and types based on their installation place. Below are the most popular sizes.

2 mm (1/16 inch) 

These are common vacuum tubings with an inner diameter of 2mm. An average 2mm hose operates between -20°C and 200°C.

3 mm (3/32 inch)

A 3mm tube is similar to a 2mm tube with the same applicability. This hose’s thickness is 3 to 4 mm, and the inner diameter is 3 mm. The 3mm operating temperature range is approximately -20°C to 200°C.

4 mm (1/8 inch)

4mm is popular on most automobiles, though its thickness can vary by manufacturer.

8 mm (5/16 inch)

The 8mm vacuum line is the larger size entry level. They are durable with better performance.

9/10 mm (3/8 inch)

You can find 9/10mm vacuum hoses in a few critical parts of the modern vehicle, such as the brakes or brake line.

They are 3-4 mm thick and appropriate for components requiring high vacuum advance performance in a short time.

12 mm

These are rare in midsize cars and handle more PSI than smaller vacuum hoses.

How To Tell Your Vacuum Hoses Car Are Bad?

vacuum line car
Your Vacuum Hoses Car Are Bad

Engine Warning Light Comes On

A vehicle’s engine includes ECU (or engine control unit). This device features sensors in the engine compartment, letting you know when something wrong happens to your car.

Also, this sensor will monitor the vacuum cleaner and alert the ECU when the pressure goes below or above normal levels. So, the ECU will trigger the check engine light to warn you of a failure.

Engine Power Loss

A vacuum hose leak may also cause power loss in your engine. Under the pressure of a sensor in the combustion engine chamber, the engine cuts power.

Rough Engine 

You can notice the engine’s feel and sound while running. If it’s running normally, you will hardly hear any unusual sounds.

Yet, the car starting rough then smoothing out can trigger a lot of engine noise, one of the vacuum pressure signs related to blown hoses.

Engine Misfire

Misfires are unpredictable and scary. Spark plug misfires cause engine misfires, but problems may also happen when a vacuum leak appears.

A vacuum leak creates excessive pressure in the engine combustion chamber. This pressure can lead to backfiring if you don’t relieve it in several ways. And the engine will stall and refuse to start.

How To Inspect And Replace A Bad Vacuum Hose?

where is vacuum hose in car
how to do when you found a bad vacuum hose

A Bad Vacuum Hose Inspection

1. Conduct a visual and physical inspection by lifting and securing the hood.

2. Locate the position of the car’s vacuum hose.

3. Double-check for rupture at the hose end. These may compromise the vacuum seal and let air enter the walls of the tube.

4. Inspect the hose clamps’ condition. Turn them back and forth to make sure they do not rattle. If the clamp moves slightly, tighten it or change it.

5. Check for bulging or swelling symptoms to seek abnormalities in the hose.

6. Examine the hose for scratches or cracks caused by ozone damage or the hose rubbing against moving engine components.

A New Vacuum Hose Replacement

1. Lift and secure your vehicle’s hood.

2. Locate the vacuum hose.

3. Take out or loosen the hose clamps using a plier or screw.

4. Take the vacuum hose out by grasping the clamped components, twisting them to release, and pulling the hose while keeping the other end.

5. Route the vacuum hose with a proper installation to prevent rubbing against hot parts, moving parts, or other hoses.

6. Insert the hoses into the fitting. Before inserting, apply penetrating oil to the hose’s inner.

7. Clamp the car’s vacuum hose. Install and tighten the right hose clamps, but avoid over-tightening them.

8. Confirm the installation by examining the new vacuum hoses to ensure they are in the right positions.

9. Reinstall the engine cover if removed.

10. Lower the hood and secure it. Contact your local mechanic for support if anything goes wrong.


What Are Vacuum Lines In A Car?

A car vacuum line is a flexible rubber or hard plastic vacuum hose carrying the vacuum in your vehicle.

Is A Vacuum Leak Serious? Can You Drive with it?

Yes, they are. Leakage is serious in common systems. A leaky vacuum can make your vehicle difficult to operate at utmost performance and full efficiency.

Besides, some automotive parts can not properly work if the car’s vacuum is faulty.

These parts comprise pop-up headlights, heater, brake boosters, cruise control, air conditioning vents, exhaust gas bypass crankcase, and valves.


A vacuum hose on a car is an indispensable part to link automotive accessories and components.

Thus, the above useful information can help you understand your car’s vacuum hoses and have proper maintenance.

This is necessary to prevent serious problems in your engine due to a damaged vacuum. Also, you can find the best solution to fix faulty vacuum hoses and give them good care.

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