In-Cylinder Pressure Test

What it is

What is a in-cylinder pressure test?

An in-cylinder pressure test measures the pressure each cylinder can build and hold, either with a screw-in compression gauge or a pressure transducer that graphs the full four-stroke cycle on a scope.

The waveform tells us far more than a single number — it shows valve timing, exhaust restriction, cranking speed and where in the cycle a cylinder loses its seal, so we can separate worn rings from burnt valves or a leaking head gasket without pulling the engine apart.

Why it matters

Why this service is required

• Compression is the foundation of every engine — no diagnosis of a misfire, rough idle or oil consumption is reliable until the mechanical condition is known.
• It prevents wasted money: replacing coils, injectors or spark plugs will never fix a cylinder that cannot hold pressure.
• A pressure test gives you an honest picture of remaining engine life before you spend money on a major repair or buy a used car.
• Catching a failing head gasket early avoids coolant contamination and a warped cylinder head.

Warning signs

When to book this service