Thread: 350 trouble

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Originally Posted by Gangi

Now when I go to start it it doesn’t crank it just makes the noise of an electric motor humming. The battery is charged but when I crawled underneath I found that the noise was definitely not coming from the starter. Btw I’m a little new to auto mechanics and this car is like a first project

JMHO, and, in my own experience, when there is only a hum from the starter (usually no click and the starter motor does not spin), it is a stuck / frozen solenoid plunger.

When this happens the solenoid coil activates (hum noise) but the plunger does not move, in turn, it does not activate the starter motor (motor does not spin) because solenoid switch contacts do not close or engage it, and the starter drive mechanism does not push out into the fly wheel (no click).

GM solenoids are usually located on top of the starter motor, which can make the noise (hum) location a little difficult for some to determine as it is coming from on top and not actually from the starter motor itself. A stethoscope or wooden dowel can greatly aid in noise location diagnostics.

An old (temporary) fix for a stuck solenoid, was to tap the solenoid (top of starter) with a rubber mallet or wooden handle.