Today, let’s talk about another really helpful tool for finding those annoying leaks that can cause all sorts of issues: the smoke machine!
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You might have heard mechanics talk about using a smoke machine, and they might sound a bit mysterious. But the idea is pretty simple: you use it to pump smoke into a sealed system in your car, and if there’s a leak, the smoke will come out, showing you exactly where the problem is. It’s like giving your car a little smoky bath to find the holes!
Smoke machines are fantastic for finding leaks in systems that are supposed to be airtight, especially vacuum leaks and leaks in the EVAP (Evaporative Emission Control) system, but they can also be used for exhaust leaks and even some less common issues.
Types of Smoke Machines
When you look into smoke machines, you might notice they aren’t all the same. One key difference is how they create the pressure to push the smoke:
- Machines with a built-in pump: These are often more convenient because they have everything you need in one unit. You just connect it to a power source (like your car’s battery) and the system you want to test, and the machine generates the smoke and the airflow.
- Machines without a built-in pump: These machines create smoke, but they require an external air source, usually an air compressor, to push the smoke into the system. Although they are cheaper, it gets really annoying using one because you have to carry a compressor as well.
Most automotive smoke machines use a special smoke-producing fluid (often a type of mineral oil or baby oil) that is heated to create the smoke. It’s important to use the correct fluid recommended for your machine.
Best Uses for a Smoke Machine
A smoke machine is your best friend for finding leaks that are too small to see or hear easily. Some of the best uses for a DIYer include:
- Finding Vacuum Leaks: These can cause rough idle, misfires (like we talked about!), and lean running conditions. Pumping smoke into the intake system makes even tiny vacuum leaks visible.
- Diagnosing EVAP Leaks: Issues with the EVAP system can cause a “Check Engine” light and related trouble codes. A smoke test is often the most effective way to find the source of these leaks, which could be a loose gas cap (start with checking that first!), a leaky hose, or a problem with a vent or purge valve.
- Checking for Exhaust Leaks: While sometimes you can hear an exhaust leak, a smoke machine can help pinpoint the exact spot, especially for small leaks that might be causing issues like a rotten egg smell or affecting oxygen sensor readings.
Using a smoke machine is a much more efficient way to find leaks compared to just spraying carb cleaner or propane around the engine bay, which can be less effective and potentially dangerous.
PRO TIP:
Small leaks can sometimes be hard to see, and having a laser pointer will ease the job. Or like in my case, a laser temperature meter from aliexpress for $6.
(Also, don’t forget that the smoke machine comes without oil, so order baby oil or paraffin oil as well if you want to use it ASAP)
Adding a smoke machine to your diagnostic toolkit can make finding those hidden leaks a much simpler and more visual process!
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