How do you tell if the starter is bad on 1981 El Camino?
Take the car to a repair shop and have them do an electrical systems test. It should include testing the starter for the amount of current dtraw it has. Also the alternator for amperage and voltage output and the state of the alternator. If the battery is low then you will get a bad starter reading.
After making absolutely sure the battery is fully charged, all the connections are clean and tight and the starter selinoid is working properly: The the engine refuses to turn over, the starter is probably bad. The engine turns over very, very slowly, the starter is probably bad. The engine starts to turn over and you hear a whirring noise, the starter is probably bad.
Not sure if its the starter or the battery? Check the battery at a store. They can do a check on it for free. If its good then the starter could be bad. Bad starters don't work or they work intermittently. Usually just ehear a click and then when you retry it starts. That's the symptoms. Most places can also check the starter for you.