Smoke Testing

What can I find with a smoke machine besides EVAP leaks?

A smoke machine finds intake vacuum leaks, boost leaks, exhaust leaks, wind and water leaks, and some oil and coolant leak paths, often in minutes.

Can I smoke test an EV or hybrid battery enclosure?

Short answer: Some smoke machines are designed for EV battery enclosure leak testing, but only follow the vehicle maker's procedure with trained technicians, since the pack contains high voltage.

Electric vehicle and hybrid battery packs are sealed to keep water and dirt out. After collision damage or pack service, makers may require a seal or leak test. Some smoke and pressure test machines include adapters and settings designed for this work.

This is high-voltage territory. Only technicians trained on the specific vehicle should work around the pack, following the maker's procedure for disabling the high-voltage system, verifying zero voltage and using insulated gloves and tools.

Check the vehicle maker's service information for the approved test method, pressure limits and adapters. Using too much pressure can damage seals or the enclosure. Use equipment specifically designed for enclosure testing rather than improvising with shop air.

How do I find boost leaks with a smoke machine?

Short answer: Seal the intake or turbo system with adapters, introduce smoke at low pressure, and look for smoke escaping at hoses, intercoolers and couplers; some kits include turbo adapters for this.

Boost leaks cause low power, underboost codes and poor fuel economy. Leaks often appear only under pressure, at clamps, couplers or the intercooler. A smoke machine fills the intake tract with visible smoke so leaks show up.

Turbo test kits include adapters to seal the intake tube and system. Use the pressure the smoke machine maker allows, and do not exceed the system's limits.

Use smoke machines designed for automotive use, keep the engine off during testing, and work in a ventilated area. Wear safety glasses, and remove the adapters before starting the engine.

Can a smoke machine find exhaust leaks?

Short answer: Yes; introducing smoke into the exhaust system with the engine off shows leaks at manifolds, gaskets and joints, which helps locate exhaust leaks that affect sensors and noise.

Exhaust leaks before the oxygen sensors can affect readings and fuel trims. They can also cause noise and fumes entering the cabin. Locating small leaks by ear or by feel is difficult and risky when the exhaust is hot.

With a cool engine, seal the tailpipe with an adapter and introduce smoke. Smoke escapes at cracked manifolds, leaking gaskets or loose joints.

Make sure the engine is cool and turned off, since exhaust parts get very hot. Wear safety glasses and gloves, and support the vehicle on a lift or rated jack stands to inspect underneath.

What is different about smoke testing heavy-duty trucks?

Short answer: Heavy trucks have large intake, air brake and exhaust systems, so heavy-duty smoke machines use higher output and truck adapters to fill bigger volumes and connect to larger fittings.

Truck intake and charge air systems are much larger than passenger cars, so a small smoke machine may take a long time to fill them. Heavy-duty machines produce more smoke and include adapters for larger hoses and pipes.

Truck smoke tests help find charge air cooler leaks, intake leaks and exhaust leaks. Some kits include adapters for air brake systems and other truck fittings.

Follow the machine maker's pressure limits and instructions. Chock wheels, set the parking brake, keep the engine off, and wear safety glasses. Ventilate the work area.