The leakdown tester is less common, and you need to get a good one to do the test properly. A compression test is to determine how much pressure the engine makes, and a leakdown test measures its ...

Compression testing is another good tool to use when diagnosing an engine. Combining the results of a leak down test with a cranking compression test can indicate an engine's potential.

While an engine compression tester may not be the most common tool in a mechanic's garage, they can be very useful, especially for older cars.