Cylinder Leakage Tester

The Moroso Cylinder Leakage Tester (SKU MOR89600) is a precision diagnostic tool designed for engine technicians and serious DIY mechanics who need to evaluate cylinder compression integrity without removing the engine. This mechanical leak-down tester identifies internal leaks in pistons, rings, valves, and cylinder walls by measuring the percentage of air pressure lost during a controlled test cycle. Properly diagnosing cylinder sealing issues saves time and prevents costly over-specification of repairs.

This analog leak-down tester operates on a straightforward mechanical principle: compressed air is introduced into the cylinder at top dead center, and the instrument measures how much pressure escapes through leakage pathways. The kit includes a 4-foot hose that connects the gauge to an external air source, allowing safe, controlled operation without requiring engine startup. The analog pressure gauge provides real-time, easy-to-read feedback, eliminating electronic dependencies and ensuring reliable field diagnostics in any environment. At 2.78 lbs with compact dimensions of 7.5 x 4.7 x 14 inches, the complete kit remains portable and shop-friendly for both bench and on-site testing.

Technicians across automotive repair shops, fleet maintenance operations, and restoration facilities rely on cylinder leakage testers to differentiate between worn rings, stuck valves, and head gasket failures—distinctions that compression-only tests cannot provide. The Moroso leak-down tester is compatible with all four-stroke gasoline and naturally aspirated diesel engines, making it essential for pre-purchase vehicle inspections, post-rebuild verification, and troubleshooting performance complaints. A leak rate below 20% indicates healthy cylinder sealing; rates above 30% point to specific wear patterns that guide repair decisions and budgeting.