One sound is a click, the other is a whir. Which do you hear? A click or rapid series of clicks suggest the battery isn't strong enough to turn the engine. A constant whir without the engine cranking/turning suggests the starter needs repair or replacement.

Go easy on the nuts you loosen. More importantly, go easy on tightening. It takes experience (or a torque wrench and specifications) to tighten them without overtightening them. Overtightening can lead to leaks down the road.

Sixto
87 300D