How to Check Engine Vacuum Hoses

Reviewed by Charley Helvy

Last Updated: December 9, 2023 References

Knowing what faulty vacuum hoses look like is an important part of keeping your car in good condition. Many of these hoses control your car's idle, emissions components and environmental controls such as your heat. This article will tell you how to check engine vacuum hoses.

Get Car Support Solve Any Problem

Hi there! Do you have a question about how to diagnose or fix a problem with your car? I’ve read the manual so you don’t have to. Select your make, model, and year, then ask away!

*

Method 1

Method 1 of 2:

Visual and Hands-On Inspection

Download Article

{"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/7\/78\/Check-Engine-Vacuum-Hoses-Step-1.jpg\/v4-460px-Check-Engine-Vacuum-Hoses-Step-1.jpg","bigUrl":"\/images\/thumb\/7\/78\/Check-Engine-Vacuum-Hoses-Step-1.jpg\/aid1179998-v4-728px-Check-Engine-Vacuum-Hoses-Step-1.jpg","smallWidth":460,"smallHeight":306,"bigWidth":728,"bigHeight":485,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}

1
Check each hose for bulges and swelling. If a hose feels soft or spongy when you touch it, this can indicate damage caused by your car's oil. ^{[1]
X
Research source}
- A swollen hose that is cracked and hard is often caused by heat damage. These hoses can be too close to heat sources under the hood or it may be the result of overheating.
- Bulging hoses can also be caused by electrochemical degradation when there's a coolant leak dripping onto hoses. Sometimes you can feel tiny cracks or weak spots when you squeeze a cool hose near one of the ends.
{"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/8\/87\/Check-Engine-Vacuum-Hoses-Step-2.jpg\/v4-460px-Check-Engine-Vacuum-Hoses-Step-2.jpg","bigUrl":"\/images\/thumb\/8\/87\/Check-Engine-Vacuum-Hoses-Step-2.jpg\/aid1179998-v4-728px-Check-Engine-Vacuum-Hoses-Step-2.jpg","smallWidth":460,"smallHeight":306,"bigWidth":728,"bigHeight":485,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}

Small parallel cracks in the cover of a hose can be ozone damage. Scratches and other irregular injuries to the hoses can be caused by hoses rubbing against a moving part of the engine. ^{[2]
X
Research source}

Method 2

Method 2 of 2:

Using a Vacuum Detector

Download Article

{"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/d\/dd\/Check-Engine-Vacuum-Hoses-Step-3.jpg\/v4-460px-Check-Engine-Vacuum-Hoses-Step-3.jpg","bigUrl":"\/images\/thumb\/d\/dd\/Check-Engine-Vacuum-Hoses-Step-3.jpg\/aid1179998-v4-728px-Check-Engine-Vacuum-Hoses-Step-3.jpg","smallWidth":460,"smallHeight":306,"bigWidth":728,"bigHeight":485,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}

^{[3]
X
Research source}
{"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/a\/a3\/Check-Engine-Vacuum-Hoses-Step-4.jpg\/v4-460px-Check-Engine-Vacuum-Hoses-Step-4.jpg","bigUrl":"\/images\/thumb\/a\/a3\/Check-Engine-Vacuum-Hoses-Step-4.jpg\/aid1179998-v4-728px-Check-Engine-Vacuum-Hoses-Step-4.jpg","smallWidth":460,"smallHeight":306,"bigWidth":728,"bigHeight":485,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}

2
Attach your vacuum gauge and start your vehicle's engine. Allow your car to idle for a couple of minutes. Your gauge should read between 14 and 18 inches of vacuum.
- If the reading is low or non-existent, there's a blockage or leak in the vacuum line. Visually check the entire length of the hose for the problem.

Community Q&A

Search

Add New Question

Question

My truck has a rough idle but when I remove the vacuum line it smooths out. Why is this?

Community Answer

It depends on what part it is. On my 1999 Ford Ranger 4.0 V6 I had to replace the canister purge valve and I had almost the same situation. When you open the hood it should show a diagram with the vacuum hoses and the various places they go to. On mine it's the charcoal bed to the canister purge valve then to the throttle body. It wouldn't be the IAC so no worries there. It mainly depends on what truck it is.

Thanks! We're glad this was helpful.
Thank you for your feedback.
If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
Yes No

Not Helpful 0 Helpful 2
Question

How long can I drive with a faulty vacuum hose?

Community Answer

You can drive it, but not repairing it will ruin your fuel economy and create possible damage to an expensive catalytic converter.

Thanks! We're glad this was helpful.
Thank you for your feedback.
If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
Yes No

Not Helpful 3 Helpful 2
Question

I accidentaly disconnected when cleaning my car and was confused as to where to connect the vacuum hoses for my LN130 Toyota turbo engine. Can anybody help me?

Community Answer

Look on the top of your engine for a small disc object (might look like a flying saucer). There should be a small tube on the top of it. See if you can fit the vacuum hose back on tube.

Thanks! We're glad this was helpful.
Thank you for your feedback.
If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
Yes No

Not Helpful 4 Helpful 3

Ask a Question

200 characters left

Include your email address to get a message when this question is answered.

Submit

Tips

Some leaks are not visible during the visual inspection. In these cases, using a vacuum detector in conjunction with a hands-on examination can be useful.

Thanks
Helpful 0 Not Helpful 0
If you are unable to locate a suspected leak, take your vehicle to a mechanic's shop where there's more sophisticated detecting equipment.

Thanks
Helpful 0 Not Helpful 0
A hissing or vacuum sound can sometimes be heard if the leak is big enough.

Thanks
Helpful 0 Not Helpful 0

Submit a Tip

All tip submissions are carefully reviewed before being published

Submit

Thanks for submitting a tip for review!

Things You'll Need

Flashlight
Vacuum detector (optional)

[1]

[2]

[3]

Log in

How to Check Engine Vacuum Hoses

Steps

Get Car Support Solve Any Problem

Visual and Hands-On Inspection

Using a Vacuum Detector

Community Q&A

Tips

Things You'll Need

You Might Also Like

References

About This Article

Reader Success Stories

Did this article help you?

Quizzes

You Might Also Like

Featured Articles

Trending Articles

Featured Articles

Featured Articles

Watch Articles

Trending Articles

Explore Categories