When Is It Time to Replace a Car Vacuum Hose?

February 16, 2012

A leaky vacuum hose is a frequent cause of poor engine performance. Learn the symptoms of a vacuum leak, how to locate it, and how to replace the hose.

Vacuum Hose

A bad car vacuum line can cause some pretty serious runability issues with virtually any car motor. That is because the sophisticated fuel injection systems that modern cars use to meter fuel rely on vacuum to help the engine computer determine the precise engine condition. The computer then uses that information to decide how to calibrate the pulse and pressure of the fuel injectors. If there is a vacuum leak, the computer cannot gather accurate information and is forced to run the motor in a fuel-rich format to avoid creating a "lean" condition which could result in fuel detonation and possible engine damage. Here is a guide to diagnosing and replacing a leaky vacuum hose.

Symptoms of a Leaky Vacuum Hose
A car with a bad vacuum line will often have a rough and/or "lopey" idle. A lopey idle is uneven--the car's engine speed will fluctuate up and down as the engine computer struggles to find an equilibrium. Upon acceleration, the car will lack power and respond slowly to throttle input. You will also notice a decrease in fuel mileage because the engine computer will be adding extra fuel to the cycle in order to avoid lean detonation. If your car's motor is displaying these symptoms, a bad vacuum line may be to blame.

Locating the Vacuum Leak
To locate the vacuum leak, park the car in a safe and accessible area and pop the hood. With the motor running, first stand and listen to see if you can hear the leak. Vacuum leaks are often marked by an audible hissing noise created by air being drawn through the failed hose. Being careful of the engine's hot and moving parts, reach into the engine compartment and gently move the vacuum hoses around to see if you can locate the hose that is leaking. When you move the leaky hose the sound will change and the motor may respond by running differently. Move the hoses one by one until you find the culprit, then feel along its length in order to find the exact point where the hose is leaking. The leak itself should suck your fingers onto it and you will probably notice an immediate difference in the way the car idles.

Replacing the Hose
To replace the hose, purchase a length of new hose to take its place. You can remove the hose and bring it to an auto parts store to purchase your replacement, or if you need use the car to drive to the store, you can also simply plug the leak using duct tape for a temporary fix. Vacuum hoses are pretty cheap, generally around a dollar a foot, so it is a pretty minimal investment. Once you have your replacement length of hose, remove the old hose by simply holding the connections at either end and pulling on the hose with a twisting motion. The old hose should come off fairly easily. To install the new hose, lubricate it with a bit of moisture and use the same twisting motion to seat it on the connection at either end.

Related Questions and Answers

What is Required to Replace a Car Air Hose?

A car air hose is easy to replace and it's much like replacing an air filter but with a little extra work. First, obtain the correct air hose or the air hose assembly you want to use. Then, remove the air filter cover and air filter and trace the air hose from the base of air intake assembly to the front of the engine. Next, loosen any clamps you find and gently slide the existing hose off, being sure to save the clamps. Now, place the clamps on the new hose and slide the hose in place, tightening the clamps. If an electronics module is involved, don't forget to remove and replace it, once the hose is in place. Afterward, just replace the air filter and filter cover.

Where Can I Buy an Auto Vacuum Hose?

Auto vacuum hose is available wherever you can find automotive cleaning and detailing products. For example, if you were to use the Meguiar's website, you would find not only the vacuum, but also its hose. You can also find auto vacuum hoses at major auto suppliers such as AutoZone of PepBoys. Automotive vacuums are very specialized pieces of equipment that are usually equipped with long, flexible hoses. The hoses are angled so that they can fit into spaces such as between seats, under seats and under cushions. They are also among the more powerful vacuums you will find. If you need a standard engine vacuum hose for a PCV valve or similar device, you can also find one at the same sites.

How Often Do You Need to Replace Automotive Air Conditioning Hoses?

Automotive Air Conditioning hoses are actually part of the heater system as they make use of the radiator as well as their own intercooler system to remove heat from your car. Because they are part of the heater system, you should have them replaced on the same schedule that you replace other hoses. On average, all hoses should be checked at least once a year and if they feel spongy or there is seepage from C-clamps, it means the hose needs replacement. Since all hoses are usually installed at once, it would pay to replace them all at the same time. You should get at least three years from your hoses.

What are the Benefits of Installing an Auto Vacuum Gauge?

The benefits of installing an auto vacuum gauge are simple; the gauge indicates your instant mileage, based on manifold pressure, so that you can adjust your driving habits. High readings on the vacuum gauge indicate high pressure in the manifold and this means you are using less gasoline. Low readings on the vacuum gauge indicate low manifold pressure that translates into high gasoline use and poor mileage. It is probably the best instant method of monitoring your current miles per gallon usage as the readout changes instantly with pressure on the accelerator. You can use this gauge to correct poor mileage habits the same way, instantly.

What Does an Automobile Vacuum Do?

An automotive vacuum is simply a powerful shop vacuum that is specially made to clean and prepare cars for sale or is used by a detailing shop to give the interior a total cleaning. Made in two parts, it consists of a large tank/waste container onto which the motor of the vacuum attaches. Minimum cleaning power is 11-horsepower or better through a specially fitted coiled hose that is about three inches in diameter and fitted with an angle-shaped nozzle to fit between seat cushions, under seats and pedals, and into the channel between the doors and seat tracks.

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