Is your car idling roughly? Do you hear a hissing sound? Is your check engine light on? These are signs of a vacuum leak. Leaks can be easy to fix, but notoriously hard to find — unless you know how with this simple life hack.
How do you find a vacuum leak using a cigar?
- Use a code reader to see if a vacuum leak is the problem and where
- Take off the hose
- Light the cigar and blow the smoke into the hose
- Look underneath the vehicle to see where the smoke is exiting
As a professional mechanic, Scotty Kilmer has a professional smoke machine for finding vacuum leaks. The average person can’t afford that equipment, but a cheap cigar functions in the same way. Let’s look at the specifics of this life hack.
Why a Vacuum Leak is a Problem
The first and most obvious issue is that your vehicle will idle roughly and won’t perform well. Gas mileage may drop significantly, power is affected, and there are other concerns as well.
A vacuum leak allows extra air into the system. This increases the amount of oxygen in the oxygen-to-fuel ratio, which affects combustion. Your vehicle has sensors that keep this mixture at the optimal ratio, and leaks bypass the first sensor.
The O2 sensor is near the end of the system. It will notice the mixture is too lean, and may add more fuel. This can cause the cylinders other than the one with the leak to run too rich. This can lead to more problems.
How to Find a Vacuum Leak Using a Cigar
Use a Code Reader to Identify the Problem Area
A code reader can tell you if a vacuum leak is likely the problem — and the general area where it is located. It will often mention a cylinder or bank, which gives you a starting point for your search.
If you don’t own a code reader, you can purchase one online. You can also visit your local auto parts store. Many times they will provide code reading as a free service.
You can also do things the old-fashioned way. A vacuum leak will produce a hiss when the engine is running. If you hear this noise, you have a vacuum leak. You should be able to determine where it is by where the noise is coming from.
Remove the Hose
The engine should be off. If it’s recently been running, the hoses may be hot. Let things cool down before moving on. Once you know the problem area, remove one of the vacuum hoses from that area.
You’ll need to have another loose hose to put in its place or place something over the open area to prevent smoke from escaping through it. Duct tape works well.
Blow Smoke into the Hose
Light the cigar. You’ll need to smoke the cigar to produce the smoke. Draw on the cigar but don’t inhale. Blow the smoke into the hose. Once you see smoke coming out from the engine area, you are ready for the next step.
Follow the Smoke
Now you can simply follow the smoke to find the leak. If you don’t see the source from the top, check from underneath the vehicle. It should be easy to find the exact spot the smoke is coming from.
Repair the Leak
Many times, a repair is as simple as replacing a hose that has slipped off. If there’s a hole in the line, it will have to be replaced. If it isn’t sealing properly at the connection point, a new hose clamp might do the trick.
Once the leak is repaired, and all hoses are back in place, start the engine. It should be idling normally without any hissing sound. If it’s running normally but the check engine light is on, you may need to reset the computer.
Learn More About Your Car
Scotty Kilmer is a substantial source of information for car care, but he’s not the only source of information you should know about. You should also check out Vehicle History. You can learn about the history of your vehicle, common problems, and read owner and expert reviews.
