Test Evaluation
- The test does not show any meaningful result on a new engine (i.e. one that hasn't been run in).
- A difference in pressure loss between the individual cylinders of approx. 5% is not significant.
- If the test shows an excessive loss of pressure (> 30%), a few drops of oil can be sprayed into the combustion chamber. Repeat the test. If the loss in pressure is now significantly less, the seal between the piston and cylinder is damaged.
- The air that is escaping causes hissing noises, which provide information about the component that is causing the damage.
If the limit values are exceeded, the engine must be started and the test repeated.
Potentially faulty component Location of noise Pistons, piston rings, cylinder line Oil filler neck, positive crankcase ventilation Cylinder head gasket, cylinder head Coolant expansion tank Exhaust valve Exhaust system Inlet valve Intake system