Freeze plug with the "sensor plug"

[Yehoshua]

I had the machine shop replace my freeze plugs but when I got it home and looked they did not replace the one that looks like it has a "sensor plug in" on it. Is this normal and does it need replaced also?

[DmaxMaverick]

That plug, which should be located between cylinders #3 and #5, is the block heater. If you never use it, you don't need it. If you ever need it, it won't be there. It isn't essential to run the engine, but can be very helpful for very cold starts. It doesn't "do" anything by itself. If you don't plug it into a 120V outlet, it does nothing.

[Yehoshua]

Oh ok... Does the black heater normally get replaced during a rebuild?

[DmaxMaverick]

They are normally replaced during overhaul. They are relatively inexpensive, and easy to do with the engine out of the truck. Not too bad, even with the engine in the truck, but requires a coolant drain/fill. Again, if you don't need it or won't use it, don't worry about it. Most folks don't even know they have it.

[Dvldog8793]

Howdy
since it looks like you live in West VA...you probably wont ever need to use the block heater. It is very similar to an electric water heater element with an o-ring and clamp seal. Pretty trouble free most of the time.
If you do want to use it....
Assuming it still has a cord on it...the cord will normally be found coiled up someplace behind the driver side of the radiator low in the engine compartment. Just uncoil it and plug it into 120Volt. In a few minutes, you will actually hear the coolant start to bubble and circulate. In about three - four hours it will have the coolant temp in the block up about 90 degrees.
I normally plug my rigs in when the temps drop to below 15 degrees F.
As Dmax said ...Many people in the south don't even know those plugs are there and the never get used.

Hope this helps...

[Yehoshua]

Thanks for the replies