Block Heater Unplug first mandatory?

[RickB]

I can't see why a bubble would form there. It's in the middle of the block. It should help cool the element with the coolant circulating. . I sometimes Idle the engine with a block heater still plugged in always wondering if it will heat up faster.

But, I won't do it, until I get a good answer.

I agree. The water pump pushes water INTO the block from the lower radiator tank. That means the coolant in the block is under positive pressure. If the block is free of air pockets, it will stay free of air pockets. Flow will be super low at startup due to the thermostat being closed; the only flow out of the engine will be via any coolant bypass. I call the heater MFG's warnings an unnecessary CYA stunt.

 

[RNeumann]

I did some reading about the "air bubble" with regards to the block heater. The "air bubble" answer was in response to failure immediately after install. They also discuss failure if you bench test the heater by plugging it in. In both cases the element will overheat and fail because it's not immersed in fluid.
The the "air bubble" in question is formed when you drain your block to install the heater and then plug it in without fully filling and "burping" the coolant system.
The theory behind not leaving it plugged in after starting is two fold. One is so you don't drive off with cord plugged in (or cake on the roof) and the second would be boiling. The boiling could lead to an air bubble and element failure.
Before you ask- the elements are sized to the block and vehicle with several sizes and power outputs. They are designed to bring the coolant up to a nice temp with cold outside air and the engine generating no heat. If the vehicle is running the heater could bring the coolant around the element to a boil when the thermostat is closed. This scenario is very unlikely but one some engineer somewhere was able to get into the literature. Or someone (like a trucker) complained about failure after starting and idling the vehicle for hours with it plugged in.

All this from a blown fuse? I need to get on the tractor/out more!

 

[skyhook]

Your water heater continue's to work ( element's ) when you shower, think about it.

 

[FatTire]

On the KATS website,the reasoning is the heater element is subject to damage from engine vibrations when the element is hot-as in plugged in or shortly thereafter.
I must admit I unplug and start and have not suffered any damage,but if I do,I'll have no one else to blame.
Hope this helps!

My first Kubota block heater started tripping my GFI protection. At that point I discovered a tiny amount of coolant leaking out around the electrical pins. I had probably only used it about 10 times. When I dropped by the local dealer to order a new one, he said they stock a lot of block heaters because they are too fragile and fail "constantly". So I think unplugging before turning over the engine is probably a good idea.

 

[dnw64]

I just had an idea I'm going to try out next year.

I had bought a TP-Link Smart Plug kind of on a whim, because I thought I might find a use for it, and now I have.

It connects to your wifi and you can turn it on/off from your phone.

So I am going to plug my block heater into it (need to verify that it's under 1800 watts), and then I don't have to go out into the garage ahead of time.

 

[Looking4new]

I have both the Jeep and the tractor on remote plugs. The remotes are a little battery operated push button affair, I plug the block heater cord and a splitter with led xmas lights on it into the thingy and turn the juice on from the house.

I think you will find the block heater is about 400 watts. If you can lay your hands on a kill-a-watt meter, you can determine exactly what you are drawing.