what is a leak down test
Compression Testing vs. Leak Down Testing. There has been great confusion encountered regarding compression tests and leak down tests. A compression test is typically done prior to a leak down test and is an easy way to determine the internal health of your engine. You can have a qualified mechanic do this or you can do it yourself with the proper equipment in about 10 â 15 minutes. A leak down test may also be called a cylinder differential test.