Gnhydxfe TU-21 Engine Cylinder Leak Down Tester Kit — Dual-Gauge Compression Tester, Red, Regulator & Adapters

This compact kit gives technicians and DIY mechanics a fast, reliable way to evaluate an engine's sealing condition without removing many components. Equipped with a two-scale gauge, pressure regulator and a selection of adapters and hoses, the TU-21 works with most petrol engines that accept spark plugs. It’s designed for straightforward setup, visible readings, and flexible connection options so you can pinpoint where compressed air escapes during service checks.

How do I set up the TU-21 kit for a leak down test?

Setup is simple: plug the manifold into your air hose, screw or push the appropriate adapter into the spark plug well, and adjust regulator pressure on the manifold. Remove ignition and fuel as required by your vehicle’s safety procedures before pressurizing the cylinder to test leakage.

• Attach 18" hose to compressor and manifold assembly.
• Select threaded or push-on connector matching the spark plug bore.
• Use the regulator knob to set test pressure, then read dual gauges.

What readings will the dual gauges provide and what do they mean?

The TU-21 displays both absolute test pressure (0–100 psi / 0–7 bar) and percentage leak rate (0–100%). Together they show how much pressure you’re supplying and how much is escaping, making it easier to compare cylinders and locate problems.

• Left gauge: supply pressure in psi/bar for test consistency.
• Right gauge: leak percentage to evaluate cylinder sealing performance.
• Accuracy approximately 0.5% for repeatable comparisons across tests.

Which leak paths can this tool help identify?

By pressurizing one cylinder at a time, you can detect where air is escaping — for example past piston rings into the crankcase, through intake/exhaust valves, or into the cooling system via a head gasket. Listening, observing oil/fumes, and using the kit’s readings together improve diagnosis speed.

• Ring sealing issues: hissing from oil fill or crankcase vents.
• Valve leaks: air audible at intake or exhaust ports.
• Head gasket or crack: air bubbles in coolant or exhaust smoke.

What accessories are included and how do they expand compatibility?

The package bundles a double-gauge manifold, multiple metal adapters, push-on connectors, an extension rod, and an extra hose so you can reach a variety of engine layouts. This assortment reduces the need for additional purchases and adapts to shallow or deep spark plug wells.

• Two metal threaded adapters and push-on connectors for most petrol engines.
• M14 aluminum extension rod and extra hose for hard-to-reach plugs.
• AR2000 pressure regulator and American quick-connect fitting for easy compressor hookup.

Who is this for? The Gnhydxfe TU-21 is aimed at home mechanics, mobile technicians, and small garages that need an affordable, portable diagnostic tool for routine engine evaluation. If you perform cylinder health checks, compare multiple cylinders, or troubleshoot suspected ring, valve, or head gasket damage, this kit provides clear, repeatable results without expensive shop equipment. It’s ideal for gasoline engines with spark plugs up to approximately 20 mm bore size and for anyone who prefers visual, gauge-based diagnostics over guesswork.