How do you replace the crank seal in a 1990 3.1L?

To replace the crank seal in a 1990 3.1L engine, first, ensure the engine is cool and disconnect the negative battery cable. Remove the harmonic balancer using a puller, then carefully pry out the old crankshaft seal with a seal puller or flat tool. Clean the sealing surface, lubricate the new seal with oil, and gently press it into place, ensuring it's seated evenly. Reinstall the harmonic balancer and reconnect the battery.