So, to determine the health of a head gasket, between two cylinders, try doing a bubble test.
If you believe you have a leak, but just cannot find it, doing a bubble test may be the answer.
Because, there are occasions when either a compression or leak down test, will not show a very minor leak. For example, when the leak is, between the cylinder sealing surfaces.
So, why do a bubble test? Well, when you do a leak down or compression test, there is always some leakage. It may be from rings or valves, so you may have to do next level testing.
It is done in conjunction with a cylinder leak down test.
How To Do A Bubble Test ( In Six Easy Steps )
- The first thing you have to do, is remove all the spark plugs.
- Use a cylinder leak down tester and hook it up to one of the cylinders.
- Apply 100 psi of air pressure, to that cylinder.
- Use another hose from a compression tester and hook it up, to the adjacent cylinder.
- Place that second hose in a container of water and look for bubbles in the water.
- Bubbles in the water, confirm sealing issues.
So, all cylinders need to be done. Since, there may be an occasion where, the gasket leaks only in one direction. That is, the bubble test.
Though this condition is rare, it must be understood that the purpose is to diagnose a problem. Consequently, no assumptions or short cuts can be taken.
So, there is no pressure reading with the bubble test, only a visual confirmation of bubbles in the water.
Helps Find Very Small Leaks In Many Places
- Sometimes there is a very small leak in a cylinder wall. ( From cracks or perossidy in cylinder )
- Incorrect cylinder sleeve installation. ( Possibly too much crush, causing a cylinder to distort and leak )
- Blown Gasket or leak between cylinder. ( Gasket, cylinder damage or cylinder head damage )
- Even a (MLS) gasket leaking internally. ( Because of multiple layers of material )
- Damage to a cylinder from hydro-locking. ( Water entering a cylinder )
So, as you can see, doing a bubble test, can find issues you were not even looking for.
So, if you really believe that there is a leak, between cylinders on your engine, try doing a bubble test. The primary use of this test is, when all other tests fail. Finally, easy to do and you most likely already have the necessary tools.
Thank You !