Glossary / General

leak down test

14 Episode Mentions

Too Afraid to Ask

A leak down test checks if air is leaking from an engine's cylinders. It helps find problems like broken parts that can cause the engine to run poorly.

Technical Definition

A leak down test is a diagnostic procedure used to assess the condition of an engine's cylinders. It measures how much air escapes from the cylinder when it is pressurized, helping to identify issues like worn piston rings, damaged valves, or faulty gaskets.

Hear It Discussed

"because they knew from their leak down test that all the Pressure was being escaped right through the valve"
And You Thought You Had Car Problems - These Guys Can Help Under The Hood show 43:33

"the simple things you're going to want to do just to see is, you know, what's compression tests look like, what's a leak down test look like, you know, what conditions transmission are already in."
Walt Sipp from ProCharger talks about Corvette C8 and Gen 1 Ford Lightning superchargers, OBS Ford Truck superchargers and more. CarCast 58:28

"...but Ron, I had good leak down. I understand that. But this seems to be a random problem."
Ron Ananian, The Car Doctor - February 14, 2026 - Hour 1- A Mechanics Worst Nightmare Ron Ananian The Car Doctor 28:49