Compression pressure decreases (Focus Turnier 1)

If the compression pressure drops in one of the following units, then, from experience, the reasons are as follows:

• intake manifold or intake damper - leaky intake valve
• open radiator or coolant expansion tank - defective cylinder head gasket or crack in the cylinder head
• open oil filler neck or dipstick - worn cylinder walls, piston running surfaces or piston rings
• muffler outlet pipe - leaky outlet valve

Repeat the measurement process on all four cylinders in turn. More important than absolute pressure is the same pressure values in the cylinders.