The Best EVAP Smoke Machines For Vacuum Leak Detection

Our Ford Expedition kept dying while idling at stoplights and then struggling to accelerate. I first replaced 3 broken vacuum hoses.

It still didn’t work.

So I borrowed my buddy’s smoke machine and discovered a bad EGR valve. $100 later it was purring like a kitten.

Evap leaks can be one of the hardest things to trace down. The constant misfire codes and the fuel/air mixture problems that they cause can be absolutely maddening.

9 of the top 10 Engine DTC OBDII codes can be diagnosed with a good smoke tester. Is it an O2 Sensor (PO171-P0175) or a Vacuum leak? Is it a Misfire (P0300-P0305) or a compression leak?

With the right EVAP Smoke machine, you can cut out hours of research and wasted time swapping parts. Just connect the smoke machine and follow the smoke trail.

Which One Should You Buy?

Here are some of the best EVAP smoke machines on the market.

In my opinion, the amount you pay should be directly related to how often you use it.

If you only occasionally chase down vacuum leaks, a cheaper machine is the better choice. Those P0442 Codes can be a thing of the past. When paired with P0441, P0440, or P0446, you likely have a stuck solenoid or hole in the line. A smoke machine will diagnose without you just throwing parts at the problem.

Smoke Testing For PO171 & PO174

The Evap system wants to capture fuel vapors and safely burn them or vent them. There is always plenty of vacuum created by the engine, and it can pull vapors from the top of the fuel tank.

This Evaporative system in your gas tank is extremely important for preventing explosions when the car is sitting outside on a hot summer day. However, if you have a stuck solenoid, it can allow air to be drawn in through the line, weakening your car’s power.

This is why gas cap seal failure can trigger the P0442.

In my case, my Ford Expedition’s Check Engine Light and EVAP code came back. Further smoke testing revealed that it had an intake manifold leak. At 170,000 miles, it is cheaper for me to sell it and get a new car.

Zach’s Top 6 EVAP Smoke Machines

OTC 6522 LeakTamer EVAP Smoke Machine

What We Like:

  • Commercial grade unit; produces large quantities of smoke.
  • Included Flowmeter provides an additional diagnostic tool.
  • Best choice for professional shops.

The OTC 6522 is a commercial-level machine made by a subsidiary of Bosch Auto tools for finding automotive leaks. It produces a huge quantity of smoke, which speeds up the diagnostic process and lets you get to the bottom more quickly than you can with other tools. 

It can also test a system for integrity using the scale on the front. This flow gauge helps you see different sized leaks, so you know what type of smoke flow you are looking for. This is also handy for when you connect to a dead-end line. The flow meter will indicate zero flow.

When you have a small leak trouble code, it can be nearly impossible to find the problem. This is the machine that is going to test every nook and cranny of the EVAP system and get you a clear diagnostic on holes a small as .010 inch. Further enhancing this diagnostic ability is the UV trace. This allows you to use a UV light and UV glasses to locate tiny wisps of smoke or to find areas where the smoke testing has left a residue. It also has a very distinctive smell. 

The high-performance flow control adjustment lets you control the amount of smoke that is flowing, so you have perfect visibility. You also only want about 1.5 PSI for testing EVAP systems, so the control valve lets you adjust the flow to the system you are testing.

If you’ve worked in a shop, you’ve probably used an OTC Evap machine before. This new one is half the size and has twice the power of the earlier model.

The other nice thing that you get out of this kit is all of the adaptors. The tailpipe adaptor lets you check the exhaust line for leaks, and the and Schrader valve adaptors make it easy to connect anywhere in the Evap system.

Once connected, check the rear vent valves, the purge valve, the fill tube, and all of the connected fill lines for leaking smoke. Often corrosion on the underside of the car can cause problems with these systems.

You’ll need to connect this to a shop air compressor (capable of 50 PSI) to push the smoke into the car’s emission system.

This can also be handy for testing for leaks in HVAC systems, or for trouble-shooting where a draft or ventilation problem is being caused in a room. They are also used for load balancing commercial HVAC systems on new installations.

The owner’s manual shows using this tool for testing your car’s ventilation system.

Redline Detection 95-003c Smoke Pro

What We Like:

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This is a high-quality smoke generator. It lets you easily detect leaks in all types of lines, including You’ve got one button and one knob. It doesn’t get any easier to use. The large, leak-down gauge helps you chase down those small, hard to find leaks.

The Redline Detection Smoke Pro is designed to find EVAP leaks. However, it is also great for working on any leaks in the Vacuum line, or in the intake and exhaust. (You’ll need to buy the additional balloon adapter for testing the intake system.)

With this one, you don’t have to buy any special smoke fluids. Baby oil is cheap and works great. You don’t run dye with this system, but most mechanics will argue that you rarely need dye to find a leak.

It just runs off battery power, so you simply clip the two leads to the battery and hang it from the vehicle’s raised hood while you work.

With most of these tools, you are supposed to use nitrogen or CO2 as the air source. This is because when testing an EVAP system, the mixture of shop air, the heat source from the smoke generator, and the gas fumes in the fuel line can create an explosive combination. Because Redline uses a safer heat source, you can use a stock air compressor with it.

The valve control makes it easy to control the smoke flow. Frankly, this isn’t as big of a deal that you might think as you just need the smoke to flow. But sometimes it’s nice to have a slower amount of smoke so you can see through it and find the exact location of a hole.

To make things easier, you get the halogen inspection light and all of the adapters you need for vacuum lines, evap lines, and exhaust system testing.

Compared to Snap-on and Mac Tools, this is a stellar machine that is a favorite among professional mechanics.

AutoLine Pro Leak Detector

What We Like:

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The Autoline Pro uses a lot of the same design features that folks love about the Redline model and brings down into a more affordable machine. The thick metal construction and ceramic coil help to generate a steady stream of smoke, year after year. It comes with a lifetime guarantee.

The regulator has the output locked at 1 PSI. This helps ensure that you won’t hurt any of your systems. Thanks to the steady flow of smoke, you can use it to find other leaks, such as exhaust leaks, EGR valve leaks, and manifold leaks. No minimum PSI is required, so you could even hook it up to a 12-volt air compressor if you wanted.

They sell their own smoke that you can use, but it also works with baby oil or mineral oil.

It’s a very simple, hard-to-kill machine. When you figure that a lot of shops want $100 to do a one-time smoke test, this one is a no-brainer.

Autool SDT206 Automotive Smoke Machine

What We Like:

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The Autools pipe systems detector is one of the most powerful new tools on the market. The built-in compressors eliminate the need to attach it to a shop air supply. It’s not too loud, just make a little buzz. Keep in mind that the bottom gets really hot.

You’ll notice right away that it has more gauges than most of the other tools on our list. This provides you with more granularity and angles that you can use to problem solve a more stubborn leak. You get a pressure gauge, an airflow meter, and an oil level.

As with the Redline, it just uses about 30 ml of baby oil to generate the smoke. You clip it to the car battery to power the machine and create the smoke.

Press the air mode and smoke mode button to create the smoke. You can turn up the flow to get the right amount of smoke flow. This lets you control the flow so you can have a nice, easy, 1.5 PSI for an EVAP system, or turn it up to 23 PSI for testing the exhaust system.

When you are trying to solve a lean code, these make all of the difference for getting to the bottom of things. They do make an SDT202, but it doesn’t let you control the PSI (air pressure), nor does it come with the EVAP adapter as the SDT206 does.

This tool is ideal for the shade tree mechanic is often working out in his yard or taking his skills over to his friend’s house. The on-board compressor makes this the most portable smoke tester on our list.

A 9.92 pounds, it is heavier than some of the other models, but the added portability makes up for the weight.

MrCarTool T110

What We Like:

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The MrCarTool is a strong competitor to the Autool reviewed above. It has a built-in air compressor so that it can run solely off of your car’s 12-volt batteries. This removes the need for nitrogen or an external air compressor.

As with the other models, this one uses baby oil or mineral oil to produce the smoke. It’s rated for 6 Liters of smoke per minute. An oil level indicator lets you know when it is time to refill.

This leak tester is extremely versatile. It comes with the air balloon that you can insert into an air intake for smoke testing the air intake manifold and vacuum system. This comes in handy when solving problems with turbos. It also comes with all of the adapters for the evap system.

The heater coil has to overheat protection to protect your investment and ensure that it doesn’t overheat and burn out (a problem with the cheapest smoke machines).

Smoke-Tek Vacuum Smoke Machine

What We Like:

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For the DIY mechanic who wants to try the cheapest smoke machine, this little contraption provides the basics for those one-off testing scenarios. Best I can tell, it is a re-engineered version of the Stinger Pro 2.

Made in the USA from a combination of a lot of common, over-the-counter parts, the Smoke-Tek is the basic testing tool you need while avoiding expensive EVAP testing machines.

As with most of these other models, this one comes with the leads to connected it to your car battery.

It requires mineral oil to create thick, dependable smoke for testing. When testing an EVAP system, you can use OEM approved smoke to safely test EVAP systems (although most folks just use mineral oil or baby oil).

The oversized regulator helps to protect the Smoke-Tek device when it is connected to your air compressor.

This little machine doesn’t have near the smoke output of the other tools we’ve looked at. You’ll want to make sure you are testing in an area blocked from the wind.

However, if you are trying to solve a lean-running car and need a smoke machine leak detector that you can work with for a few hours, this is an affordable option that will quickly pay for itself. Keep in mind that it only has a 3 minute run time, so you need to give it frequent breaks to keep from burning out the heating element.

Some of the frustrations I’ve heard about this unit is that the amount of smoke it produces tends to be low and the lifespan on it is fairly short.

How Do EVAP Systems Work? 

In 1971, the EPA mandated fully-sealed fuel systems. No longer could cars naturally leak fumes to the atmosphere. A highly-controlled escape port was needed.

The fuel tank has a port that is opened by solenoid when the car is turned off. This allows fumes from the lighter hydrocarbons (such as aldehyde and olefins) to escape up to an activated charcoal canister. This canister is vented out to the atmosphere when the car is off. This protects the tank from the explosion on hot days when these gasoline fumes evaporate.

Leaking fumes can account for up to 1/5th of the pollution that a vehicle creates. This system of storing and recovering the fumes can dramatically reduce smog.
When the car is started, a purge valve is engaged, causing the fumes to be sucked up into the engine where they are burned off.

If there is a leak in this system, it causes excess air to be pulled into the engine, causing it to run lean.

When there is a fault in this system, it illuminates the service engine light and generates an OBDII code.

EVAP Machine Buying Guide

How To Use Your Automotive Smoke Machine? 

I love Scotty Kilmer’s entertaining demonstration of a simple smoke machine.

  1. Fill it with the smoke fluid
  2. Remove the core from the service port and use the adaptor to connect the smoke machine.
  3. Connect it to a Compressor and start the airflow.
  4. Connect the smoke machine to a 12v or 110-volt power supply (per unit) and begin producing smoke.

Can You Make Your Own EVAP Tester?

There have been a few enterprising folks who sell a paint can with a heating element and hose out of it that looks pretty sweet. One dude went by the name Kustom Smoke. When I search for that, I see some designs that look like his under the name of “AutoLine Pro“. (It’s not like you can really trademark the idea of using a paint can, eh?)

If you are interested in building one of your own, check out this Makezine guide. I’d probably use a paint can. Just make sure that you include a fuse on it so you don’t create a mini bomb.

Taken From Youtube

What is the Best EVAP Machine For My Mechanic Shop?

You want to invest in a machine that will last for years of use. Additionally, you want one that can produce a strong flow of smoke.

For a long time, the Vacutec model was the top pick. However, their machines have gotten harder to find online. The OTC 6522 LeakTamer is currently the one I would choose for my mechanic shop. The added feature of the flow meter makes it easy to identify where there are leaks or other problems that you need to solve — even when you can’t see the smoke.

For smaller shops, the Autool offers a very attractive testing system that does not require an external air supply, making it easier to set up and use.

What is The Best EVAP Machine For Home Usage?

The Autool is an ideal choice for the home mechanic. Even if you are working on the car in a driveway, you can connect the tester to any 12v battery with the included power cable and have instant smoke with good airflow to push it through the entire system.

Where To Connect Your EVAP Smoke Machine

It depends on which system you are checking. Generally, the EVAP service port has a Schrader valve (like a car tire). You need to unscrew the center core from the Schrader valve and then use the included port adapter to connect to the evap line into that port.

Additionally, you can use a cap plug adapter and connect in place of the gas cap. However, this method does not allow you to test the gas cap gasket — a common point of failure.

Can you Rent A EVAP Tester?

Anyone who has done a few of their own tool repairs will have rented specialty tools from Auto Zone and Advanced Auto Parts. This is an affordable way to get access to tools that you will only use for a single repair. Generally, it just takes a refundable deposit to get the tool. Auto Zone online lists a combustion leak detector and an AC leak detector for rental, but I do not see any smoke machines for rent. Check with your local location to be sure.

Best Smoke Fluid For Automotive Evap Tester?

Some of the brands (such as the LeakTamer), want you to only use their specific brand. However, most of the machines can work with any mineral oil or with one of the other brand’s smoke fluids. Check with the manufacturer if unsure.

What is Used For An EVAP Smoke Machine’s Wire?

Generally, a resistive heating wire, such as nichrome wire, is used to heat the mineral oil. Some enterprising folks have attempted to build their own machines using a paint can and an air regulator. The key thing is that the pressure needs to be capped out at 1.5 PSI to protect sensitive electronic components.

Can You Use A Party Fogger?

Before you bring down the fogger for your Halloween decorations, think twice. These party foggers use a water-based smoke fluid. That water can cause harm to the sensitive electronics of your EVAP system.

Mineral Fluid that are used by the automotive testers can leave a residue but won’t hurt the vehicle. They also provide a more concentrated, controllable, flow of air..

How Long Does It Take To Fill Intake Valves With Smoke?

When testing intake and boost valves, it takes a few seconds for them to get enough smoke for it to begin flowing out around the gaskets and other leaking problems.

However, the smaller tubes of an EVAP system can begin flowing within seconds — even if your fuel tank is mostly empty.

How Long Can a Your Smoke Machine Run?

Most of these are designed to run for a few minutes at a time. They have a small reservoir of 30 ML, which is often enough for multiple tests. Some of the high-quality machines have an overload protection system to prevent overheating. However, on cheaper models, you will want to stop them every 3 minutes to protect the heating coil.

About Zachary Drumm

Hey! My name is Zachary Drumm! This site allows me to try these tools out, piddle around in the garage, and create fresh content for you. When it comes to tools, home improvement, and being a “shade tree mechanic,” you’ve come to the right spot.