How Do You Test Car Engine Pistons?
A compression test can reveal what’s happening inside a car engine without tearing it apart. The cylinder walls, valves, seals, pistons and rings all create a tight seal, allowing energy to push the piston down into the cylinder. When these parts wear out, the engine doesn’t function properly. Prepare for the test by warming up the engine. The battery must be in good condition since it will spin the engine quite a few times. Testing a cold engine will give inaccurate readings. Stop the engine and remove the spark plugs so that the starter can spin the engine freely, and then disable the ignition system. To do this, either pull the coil wire or disable the ignition coil. Insert the compression tester into one of the spark plug holes and crank the starter to rotate the engine. This builds compression in that cylinder. Move on to the next cylinder by removing the compression tester and inserting it into the next spark plug hole, repeating this procedure until you test all the cylinders. R
