How to Tell if a Head Gasket Is Blown in a Ford 302
- 1). Start the engine and allow it to idle until warm. Then turn it off.
- 2). Remove all eight spark plugs with a spark plug wrench.
- 3). Install a compression gauge into any of the eight cylinders. The design of compression gauges varies, but most gauges either screw into the spark plug open or are pressed and held into the spark plug opening.
- 4). Crank the engine with the ignition key for several seconds until the needle on the compression gauge reaches its highest point.
- 5). Record the reading of the compression gauge.
- 6). Repeat the test on the other seven cylinders and record the readings.
- 7). Compare the compression readings of all eight cylinders. If the reading of two adjacent cylinders is substantially lower than those of the remaining cylinders, a cylinder head gasket has likely blown.
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