A leak off test is a specialist test to find the cause of the abnormality. A leak down test uses a set of gauges and pressurizes the cylinder with air and measures how much of that air is escaping.
Leak Down Test Versus Compression Test Which Is Best
Cylinder leak down test vs compression test. A compression test is to determine how much pressure the engine makes and a leakdown test measures its ability to hold pressure. I understand that both cylinder leak down and compression tests are used to test for cylinder head cracks warps and gasket leaks. If you find a cylinder with low compression a leak off test will tell you why. Compression uses engine compression and leak down uses an external air supply. You cant use a leak down tester without an air compressor or nitrogen tank. In this video i show you the basics and idea behind doing a compression test and a cylinder leak down test on an engine with suspected internal mechanical issues causing a loss of compression in.
For me the leak down test far outweighs the time savings of performing a compression test. A compression test uses the engine turning to generate the compression in the cylinder for the compression stroke in which both intake and exhaust valves are closed. A leak down tester relies on an external supply of compressed air. A leak down test can tell you quite a bit more about an engines mechanical health than a compression test can. A compression test is subjective to cranking speed and temperature so its results just dont give a good enough picture of the combustion chamber condition to make an informed decision. They both test the sealing ability of the combustion chamber but the leak down can tell you how much is leaking and where its going.
If you stopped reading right now a novice might choose a compression tester. Browse recommended tools supplies for this build. The regular engine compression test uses a single gauge and measures the maximum instantaneous compression built by that cylinder. A compression tester is a stand alone tool that relies on the engines compression to build pressure in the cylinder. I understand the difference between how each works. Check the basics and look for abnormalities.
A compression test is like a general check up with your doctor.
Gallery of Cylinder Leak Down Test Vs Compression Test
