What is a cylinder leak down tester?

A cylinder leak down tester is a tool that helps check the condition of an engine’s cylinders. It measures how much air leaks out of a cylinder when it is under pressure. The tester can help find problems like worn piston rings, damaged valves, or even a blown head gasket. Unlike a compression test, which only tells you how much pressure a cylinder can hold, a leak down test shows exactly where the air is escaping.

To use a leak down tester, a mechanic removes a spark plug and connects the tester to the cylinder. Next, compressed air is then sent into the cylinder while the engine is at top dead center (TDC) for that piston. If there is a problem, the air will escape, and by listening carefully, the mechanic can figure out where the leak is coming from. For example, air escaping through the intake means a problem with the intake valve, while air coming from the exhaust pipe points to an issue with the exhaust valve.

This test helps diagnose engine problems without having to take the engine apart. It can help identify issues early, preventing bigger and more expensive repairs down the road. Whether you’re a mechanic or a car enthusiast, a cylinder leak down tester is a great tool for understanding engine health and keeping a vehicle running smoothly. Having engine issues? Call a trusted auto shop you can trust, like Ferber’s Tire and Auto for repairs.