Updated at: 29-07-2022 - By: cnbusinessnews

Imagine you’re driving to work or running errands when you notice your car’s “Check Engine” light has come on. What are your options? Don’t worry just yet. One of the possibilities is that there is a vacuum leak, which would explain why it is illuminated. The best thing you can do in these circumstances is to check for vacuum leaks. Finding a vacuum leak in an automobile can be accomplished in a number of ways. We’ll teach you how to check for vacuum leaks using brake cleaner and other methods in the following sections.

What You Need to Know About Vacuum Leaks

Let’s start by defining what a vacuum leak actually is. As the piston descends, it creates a vacuum, which pulls in air and fuel for combustion inside the engine. Fuel is drawn into the cylinder by the intake system when the piston descends into the bore.

How To Find A Vacuum Leak & How To Fix It (8 Easy Steps)

Having a vacuum leak indicates that air is able to enter the system in a non-induction system manner. That’s not good at all.

A poor gasket, cracked, damaged, or disconnected hose, or even a broken component might allow air to enter the engine and cause it to malfunction.

Think about how many other parts benefit from the engine vacuum. Engine vacuum may power anything from the power brakes to the power steering to the PCV valve and even the climate control system in the cabin. Engine vacuum systems differ from automobile to car, but it’s easy to understand how tracking down a leak may be a huge hassle.

Fortunately, a vacuum system diagram can be found under your car’s hood, on the internet, or in your dusty manual, all of which are easily accessible. In order to identify a vacuum leak, this information will not advise you exactly where to look. However, we can’t stress enough how crucial it is to thoroughly understand the system of your specific car, particularly if it has been modified.

Vacuum Leak Symptoms

There is a lean running state when there is a vacuum leak present. The fuel and air combination is thrown off, and this will have an effect on the vehicle, but the extent to which it does so will be determined by a number of variables.

Modern cars employ an O2 sensor to constantly monitor and adjust the air and fuel combination. A vacuum leak causes it to send increased fuel levels in an attempt to compensate for incoming air. As a result, you’ll typically see a spike in idle time.

Older cars with carburetors don’t have a mechanism to enrich the fuel mixture on their own. In the end, you’ll have to deal with a shaky idle and the need to add a lot of fuel in order to fix it.

The most important thing to remember from this knowledge is that discovering vacuum leaks is made simple by listening. For many of the steps below, you’re listening to changes in the engine’s running condition as you troubleshoot.

Visually Inspect Vacuum Hoses

First, examine the vacuum hoses for cracks or damaged hoses. After a few years under the engine’s heat, rubber vacuum hoses will harden and begin to split. Vacuum hoses that are damaged or broken should be replaced.

Start the Engine

Make sure the engine compartment is free of any damaged or leaky vacuum hoses and other components before starting the engine. Apply the parking brake, put the gearbox in neutral or park, and start the engine. During this tutorial, be careful not to touch any moving or heated parts!

Get a Flammable Spray Ready

Spray or gas-based flammable fluid is required for the remainder of this instruction. There are a variety of products that may be used to clean the starter, brakes, carburetors, and more. Using a carburetor cleaner or a propane torch is highly recommended for these procedures.

Make vacuum leaks hiss-tory - Old Cars Weekly

Carefully Spray Around Intake Manifold Gasket

Take the spray and try to determine where the intake manifold is attached to the cylinder head, then carefully spray around the connection on each cylinder.. If your car’s RPM or sound changes, you may have a faulty gasket in the intake manifold. If the intake manifold is divided into numerous portions, you can also try to spray around other suspected regions.

What if My Engine Doesn’t Power Vacuum-Operated Systems?

Options like power brakes may be eliminated from your vehicle. It’s possible that the car’s former owner jacked it up and threw out anything unnecessary. Alternatively, it’s possible that an electric vacuum pump was used because the engine design didn’t generate enough vacuum to power those components.

As a side note, a belt-driven vacuum pump can also be found in many current engines.

You’ll have to go through a little different process in any case. If there are no vacuum lines coming from the engine, the sole source of a vacuum leak is a problem with the intake system’s mating surfaces or the components themselves. If there is no evident damage, you can use the propane enrichment or carb cleaning tests indicated above to inspect these surfaces.

How To Find A Vacuum Leak & How To Fix It (8 Easy Steps)

Vacuum line troubles won’t have an effect on the engine’s performance if you’re using an auxiliary vacuum pump System failure will be limited to those reliant on that phantom power. As an example, let’s say that the power brake booster’s connection is the problem. Consequently, your brakes will be rock-hard since there is insufficient vacuum to aid the system, which is yet another reason why vacuum leaks must be addressed.

In most cases, all that’s required to detect the problem with this system is a visual assessment. Vacuum pump tests can also be used to check the condition of vacuum-dependent systems.


Vacuum leaks are often caused by faulty hoses. In the future, you may find yourself needing to use brake cleaners and other procedures to check for vacuum leakage. Consider wearing rubber gloves and eye protection when handling hazardous materials. The presence of an extinguisher can also be quite beneficial while inspecting for suction leaks.