93 geo prizm won't start once warmed up

Hi, I have a 1993 Geo Prizm with about 120,000 miles, it recently developed a problem where once it is warmed up, it will not start. It starts right up when it is cold first thing in the morning, but once I drive it for 15-20 minutes, if I shut it off, and then turn the key to restart it, nothing happens, no crank, maybe just a small hum. I took it to my mechanic and he cleaned the battery connection and thought it had fixed it, but the next day it did the same thing. Also, it runs fine until it gets shut off, even if I leave it running for hours, it runs fine until I turn it off and then it will not start again for about an hour. Any ideas? Thanks for your help.

Put a new starter in it. It’ll need one soon anyway.

sounds like a starter problem. Insightful is right

This is about the mileage that Toyota starter solenoids wear their contacts out. Usually you will hear a click but nothing else. If you keep turning the key to ‘start’ eventually you will get a crank.

Drive it to your mechanic warm so he/she can see the problem as it is occuring. The problem will be obvious if the tech can diagnose it.

My camry starter died exactly at 100k miles. Neighbor’s died at 125k. Replaced them both and we are stll cruising.

The copper contacts inside the solenoid wear down. You could replace them, or even bend them a bit toward the disc on the plunger. You could buy a new, or for a lot less money, rebuilt starter. You could remove the starter and take it to an auto electric shop for the repair. Depends on how much you want to do yourself to save money and/or have the experience.