ONDYNew Leak Down r Tu-21 Engine Cylinder Leak r Leakage Detector Engine Compression r Gauges Set

OEM makes a great line of reasonably priced, reasonably well made and reasonably accurate tools for the DIY automotive mechanic. Their Cylinder Leakage Tester is no exception. This tester has two different connection, Input air and Output air to cylinder. The Input connects to your 90-100psi shop air compressor with NPR Quick connect couplers and the Output connects to the cylinder under test a special Test Hose. The test hose has 14mm male threads to screw into the spark plug hole (hand tighten only) and a NPR Quick connector to connect to the Tester's Output port. Disconnect the Test hose to quickly calibrate the tester, then reconnect the Test hose and you will immediately see and hear results. Keep the ignition OFF. You may need to manually rotate the engine crankshaft with a wrench to bring the cylinder under test toward the TDC of its Compression Stroke so that the valves will both be shut and a "Good Cylinder" should not leak high pressure air being fed through the spark plug hole. Under this test condition, a blown head gasket will let high pressure air leak to either or both coolant passages or oil passages. Coolant expansion tanks may overflow as a result. Pressurized air may leak (and whistle?) from oil filler caps and /or Air-Oil separators. This tester can readily locate a blown head gasket that a Compression Test will completely miss.

This is certainly not a high end tool to compete with the professional brands but it does work as intended. This needs at least 90 psi supply pressure. No regrets with this purchase.

I like that this product worked (eventually), but the air connector was an ODD size. The male connector on the gauge side of the tool would not fit in the female side of either of my air hoses, so I had to squeeze the tool on the hose and hold it while a friend helped me connect the spark plug hose adapter. It was a PAIN! If I wasn't in a hurry to so the job I would've returned it for a properly fitting one but I needed to get the car back together.I don't have any idea why it didn't fit together, as you can see by the pics it looks like it should fit. My guess is the tolerance from the factory is off by list enough for it to work.Overall you get what you pay for but I made it work well enough

Not sure if was shown in original ad, But Compression Gauge has no 0- 300 on Gauge Face. Just Good,Bad,, and something in the middle( I forgot) anyways. No pressure relief button for Compression Gauge. Has to be used as one unit .

I like the gauges themselves, but the leaking (cheap?) female connector on the air hose from the gauges to the spark plug adapter hose caused me to return the tester. When I tried the tester with a different air hose it worked well. Because I could wait no longer to do my testing, I bought a more expensive test kit a local shop.