Humm under hood.

What is your question?

I have a problem with my 1992 toyota pick up. I went to start it today after driving to the store and it started with a high pitched humm coming from the area under the battery. Along with it, there sounds like a chugging sound also. This just came up. I checked the engine for fluids and found the radiator down in fluid. I filled it and tries again the sound remains. It wasn't overheating. This happens with the ignition on. It starts and runs but the noise gets louder.