Troubleshoot a Blown Head Gasket with No Signs

Blown head gaskets are expensive repairs, and are most often caused by an overheated engine. Some compact engine designs, however, are prone to head gasket failure under normal operating conditions. These are generally four-cylinder engines that have higher compression, aggressive fuel injection systems and are geared towards performance. These modifications stress the engine integrity and a common failure point is the head gasket, because the gasket is unable to contain the added boost inside of the cylinders.

Procedures:
1. Raise the hood of the car and use a socket wrench to remove all the spark plugs. Label the wires with masking tape if necessary to orient the wires for reinstallation.
2. Screw in a compression gauge in one of the cylinders. Have an assistant crank the engine over and read the gauge. Note the reading and compare it to the manufacturer's specifications. Small engines that are geared for performance will read as high as 150 pounds per square inch (psi).
3. Continue this process with each cylinder. Two adjacent cylinders with a blown head gasket will share the same, low reading number, and may not reach 100 psi. If the readings are as low as 125 psi on a small, performance engine, the engine won't run.