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.
There are occasions when either a compression or leakdown test, will not show a very minor leak. For example, when the leak is, between the cylinder sealing surfaces.
When you do a leak down or compression test, there is always some leakage. It may be from ring or valve, so doing the bubble test, may be the answer.
It is done in conjunction with a cylinder leak down test.
Bubble Test – How To Do It ( Seven 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 cylinder need to be done. Since, there may be an occasion where the gasket leaks only in one direction.
Though this condition is rare, it must to 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 injected to a cylinder from flooding )
So, if you really believe that there is a leak, between cylinders on your engine, try doing a bubble test. The primary use of the bubble test is, when all other tests fail. Finally, easy to do and you most likely already have the necessary tools.
Thank You !