My 89 Honda accord engine works great. No problems. After I drive around 10 -15 minutes, the engine light comes on. It stays on, until i switch the engine off. Then again. This problem started after I changed the radiator. Disconnecting the battery does not make it go away by reboot.

 

welcome to the forum. Please find a shop that will help you to get the code for free. Autozone, Amco( trans shop ) Then you can determine better what the why the light is on. changing the rad, you may have an air pocket in the area of the system bleed, did you bleed the water system. Also did you check the resovoir coolent level ( reserve tank )