Block heater making a different noise...

[craigt502]

My factory block heater always made a quiet " ssssh" noise when plugged in. Now its making a deep tone of humming. Like the sound of some kind of small electric motor.

What gives?
What noises does your block heater make?

[Falco]

Hmmm mine is silent. Theoretically a heating element shouldn't produce any sound at all. I work on 3phase 480V elements at work that pull 80 amps per leg and they are completely silent. Usually a humming noise from electricity is associated with a coil or high current. But I'm fairly new to diesels so someone may prove me wrong

[Quickhorse]

You ever find out what the noise was? I have the same thing going on plus the cord that i am using to plug the block heater in to the wall is getting hot and smelling like burnt wires. I tried a different cord and the noise is still there . . . coming from the heater element. I've already taken this thing out a couple years ago to replace the gaskets and O-rings . . . not sure what would go bad in it? I guess the coils inside it.

[madpogue]

Some of them crackle, some don't. But you really need to measure the resistance at the element, and at the plug at the end of the cord. In both cases, it should be about 15 ohms. You can also check the continuity of the cord going to the element, and replace it if needed. The extension cord you use should be fairly heavy-duty, 14 or 12 gauge (12, if it's a long cord). Remember, the element draws 1000 watts.

[Quickhorse]

Originally Posted by madpogue

Some of them crackle, some don't. But you really need to measure the resistance at the element, and at the plug at the end of the cord. In both cases, it should be about 15 ohms. You can also check the continuity of the cord going to the element, and replace it if needed. The extension cord you use should be fairly heavy-duty, 14 or 12 gauge (12, if it's a long cord). Remember, the element draws 1000 watts.

The cord I am using is about 3/4" thick and only 15' long so I know it's not that . . . the noise sounds like a small jack hammer under the hood.

[DilleyMJ]

okay, is the plug just heating the block? do they heat anything else? or just the coolant in the block?