How to Remove the Crank Sensor on a Marquisby Kyle Sanstrom
The crankshaft position sensor on a Mercury Grand Marquis is located on the left side of the engine block, approximately 6-inches above the oil pan. This sensor is designed to measure the position of the crankshaft in relation to the camshaft and engine block. The powertrain control module, or PCM, reads this sensor in order to decide when to fire the ignition. A faulty crankshaft sensor can render the engine inoperable, allowing it to crank but not fire. New crankshaft sensors can be obtained from Ford dealerships and automotive parts stores.
Place the car in park, engage the emergency brake and turn off the engine. Allow the vehicle to cool down for at least 60 minutes.
Open the hood and locate the crank sensor. It is on the bottom left side of the engine block, 6-inches above the gap where the oil pan meets the engine block. It is made from black, hi-impact plastic and has a metric steel nut holding it to the block.
Press the locking tab on the crankshaft sensor's electrical connector and remove the connector from the sensor. Remove the sensor's retaining bolt using a 1/4-inch ratchet and a 10 mm socket.
Remove the sensor from the block by hand using a twisting/pulling motion. If the sensor is too difficult to remove by hand, grip it with a slip-joint pliers and use the same twisting/pulling motion until it is free from the block.