The 7 Best Leak Down Testers

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This wiki has been updated 17 times since it was first published in January of 2020. If you are on the hunt for a leak down tester, chances are you have a serious engine problem or are trying to isolate one. Equally likely is the fact that this is one purchase where quality and accuracy are essential elements. Each option in our selection has been given careful consideration, since faulty compression results could end up costing significantly more than any of these tools. When users buy our independently chosen editorial picks, we may earn commissions to help fund the Wiki.

1. OTC 5606 for Gasoline Engines

2. OTC 5609

3. Innova 3612

Editor's Notes

February 19, 2020:

If you're trying to decide whether or not to condemn an engine, the last thing you want to settle on is the quality of your leak down tester. Any tool that does not come with gauges to measure both pressure and leakage has been omitted. In some scenarios, an engine may create an acceptable amount of compression but worn-out piston rings or valves could be allowing pressure to escape. Keep in mind that when a fitting size is listed, you should have your vehicle specifications handy and check compatibility before purchasing.

This Wiki includes options for daily, rigorous professional use like the OTC 5609, as well as others for the odd job at home in your garage like the Faersi Cylinder Leak Detector. The Lang Tools CLT-2 is a worthy contender if certain professional brands are out of your budget.

Each tester comes in a durable case except for the Innova 3612, chosen for its versatility of application and caliber. One common problem with many of the leak-down testers is the quality of the fittings. Some are poorly machined and won't thread well. Others may not be clamped on to the hose and allow air to escape during a test, thereby causing a false reading. These types of scenarios are accounted for in our ranking process to ensure every option is truly the "best of."

Unintentional damage can be caused if performing a compression test incorrectly and should not be attempted without technical training.

4. Lang Tools CLT-2

5. Faersi Cylinder Leak Detector

6. ABN Cylinder Leak Detector

7. Cheesea New Heavy Tu-21

Christopher Thomas
Last updated by Christopher Thomas

Building PCs, remodeling, and cooking since he was young, quasi-renowned trumpeter Christopher Thomas traveled the USA performing at and organizing shows from an early age. His work experiences led him to open a catering company, eventually becoming a sous chef in several fine LA restaurants. He enjoys all sorts of barely necessary gadgets, specialty computing, cutting-edge video games, and modern social policy. He has given talks on debunking pseudoscience, the Dunning-Kruger effect, culinary technique, and traveling. After two decades of product and market research, Chris has a keen sense of what people want to know and how to explain it clearly. He delights in parsing complex subjects for anyone who will listen -- because teaching is the best way to ensure that you understand things yourself.

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