Ask the Expert: Finding DPF and other exhaust aftertreatment leaks quickly and efficiently

Looking for leaks in a diesel particulate filter (DPF) or exhaust aftertreatment system can be frustrating and time consuming for technicians. Getting under the running truck to spray soapy water in the hopes that bubbles will form to help spot the leak can be dangerous and Ultrasonic listening devices can provide unclear and imprecise results.

High-pressure leak testers or smoke machines such as the Bosch HPT 500 High-Pressure Leak Tester, which is built specifically for heavy-duty vehicles and systems, can provide a quick and efficient solution to finding leaks. A high-pressure leak detector uses regular compressed air to reach and maintain a variable pressure of up to 20 psi throughout the vehicle’s intake and exhaust system.

Since many upstream component leaks only appear under boost, compressed air is injected into the system through high-pressure leak detection with the engine safely off. A visual vapor is then introduced into the system which replicates the boost load of the running engine. The dense, highly visible vapor flows throughout the truck’s hoses, tubes and related components, escaping the system anywhere there is a leak present. This process makes it easy to see exactly where problems are located with accuracy and reliability.

Information Provided By: Dan Sampson, Bosch Diagnostics