GDLIN Cylinder Leak Down Tester Kit with M14 Extension Rod — Dual‑Gauge Pressure & Leakage

GDLIN's Cylinder Leak Down Tester Kit is a dual-gauge compression and leakage testing set with extension rod and adapters designed to find piston, valve, head gasket and cylinder issues in gasoline engines.

This compact kit gives home mechanics and professional technicians a reliable way to pressurize a single cylinder through the spark plug hole and read both pressure and leakage percentage. It connects to a user-supplied air compressor and includes a regulated manifold, hoses, quick-connect fittings and an M14 extension rod so you can reach tight spark plug wells on cars, trucks and motorcycles.

How does the dual-gauge system show leakage and pressure?

The kit uses two clear analog dials: one measures pressure (0–100 psi / 0–7 bar) and the other shows leakage rate as a percentage (0–100%). Readings let you quantify how much air is escaping from the tested cylinder and help isolate the fault. Gauges are calibrated to ±0.5% for repeatable results when used with a steady compressor supply.

• Pressure gauge range: 0–100 psi (0–7 bar)
• Leakage percentage dial: 0–100% for direct comparison
• Accuracy approximately ±0.5% for consistent readings
• Analog display for quick on-vehicle checks

What fittings and accessories come with the tester?

The kit ships with a dual-head manifold, an 18-inch regulator-equipped hose assembly, multiple adapters and connectors to fit most gasoline engines. Included are universal push-in quick connectors plus threaded adapters that allow both non-threaded and threaded spark plug openings to be tested. An aluminum M14 extension rod and an additional extension hose expand reach for recessed plugs.

• Dual-head manifold and AR2000 style regulator
• 18-inch hose with quick-connect air nozzle
• 2 metal threaded adapters and 2 universal push-in connectors
• M14 aluminum extension rod plus long and short hoses

How do I use the tester safely and accurately?

Start with the engine at TDC on the compression stroke and remove the spark plug. Connect the proper adapter, attach the test hose to your compressor, and bring the regulated pressure up slowly. Observe both gauges once pressure stabilizes; listen for obvious air escape to locate leaks. Never test on running engines and always follow basic shop safety with eye protection and proper ventilation.

• Set piston at top dead center (TDC) for the tested cylinder
• Regulate compressor to the required test pressure before connecting
• Use extension rod and hoses to reach recessed plugs cleanly
• Inspect for audible leaks at valve, gasket, and crankcase vents

Which engines and spark plug holes are compatible?

This leak down tester is built for gasoline engines whose spark plug hole diameters are up to 20 mm and supports typical passenger cars, light trucks and motorcycles. The mix of push-in and threaded fittings plus the extension rod covers most modern and older engines. It is not intended for diesel engines that require different test pressures and connectors.

• Designed for gasoline engines with spark plug holes ≤20 mm
• Compatibility: cars, light trucks, ATVs, motorcycles
• Not intended for diesel cylinder testing
• Extension rod and long hose for deep-plug access

Who is this for: The GDLIN Cylinder Leak Down Tester Kit suits DIY enthusiasts, mobile mechanics and shop technicians who need a portable, accurate way to check cylinder sealing issues without removing heads. If you work on gasoline engines regularly and want a single kit that covers threaded and non-threaded spark plug holes with extension reach, this set offers the fittings, regulator and dual gauges to perform routine diagnostic leak-down checks and help prioritize repairs.