Block heater getting very hot?

[Avery4]

I'm wondering exactly how hot the outside of a block heater is expected to get. I realize that it's a heater and it's going to get hot during operation, but I think mine may be heating up a bit excessively.

Several months ago, I installed this Zerostart block heater in my K24 swapped Honda Civic and although it works well, I noticed that the exterior brass piece around the heating element and electrical connection gets extremely hot within seconds of plugging it in to the point of instantly boiling drops of water off the outside of it, which seems a bit excessive to me.

My concern is that if the outside of it is getting hot enough to boil water, I don't see what would stop the coolant inside from getting hot enough to boil and create pockets of steam, which would obviously be bad. Is this a concern?

Here is what the block heater I installed looks like in case anyone is wondering.

Thanks a lot for any input as always!

 

[hemitom]

Not sure about boiling drops of water on mine , but cannot keep my fingers on it without burning them.

 

[wwillson]

We used block heaters on every machine we wanted to start in the wintertime. You could always hear the water boiling on the surface of the element. Does it make steam, sure on the surface, but the steam condenses immediately when the bubbles float up into the cold water. Don't worry about it.

 

[carviewsonic]

It has to get hot enough to warm up an entire engine in sub zero temps. Given a block heater's small size, that must be a pretty high temp.

 

[Avery4]

Not sure about boiling drops of water on mine , but cannot keep my fingers on it without burning them.

I definitely can't either, once it's been plugged in for a few minutes I can only touch it for a fraction of a second. I burned the back of my hand on it pretty good by accidentally touching it while I was trying to plug in the oil pressure switch right by it.

 

[short]

Coolant in a sealed system is pressurized raising the point of boiling way above the 212F in our standard atmosphere. There is a chart out there somewhere.

 

[hemitom]

I definitely can't either, once it's been plugged in for a few minutes I can only touch it for a fraction of a second. I burned the back of my hand on it pretty good by accidentally touching it while I was trying to plug in the oil pressure switch right by it.

I think your block heater is functioning as designed !

 

[Avery4]

Coolant in a sealed system is pressurized raising the point of boiling way above the 212F in our standard atmosphere. There is a chart out there somewhere.

I agree, but the system isn't necessarily significantly pressurized because the block heater doesn't heat enough of the coolant hot enough to change the overall volume very much.

 

[Little_Lebowski]

On my 7.3 PSD the block heaters are 1K watts. I have the electric bills as proof.
Never had a over heating issue.

 

[Avery4]

So far, this block heater seems to still be working out. I have been using it for a few hours before starting whenever possible even in 50-60+ degree weather and it's still working fine with no signs of any problems.

Just out of curiosity, how much would using a block heater frequently for a few hours before startup increase the coolant degradation? Surely that localized heating would somewhat increase coolant degradation, but by how much? I'm not concerned about the coolant degrading since I regularly service my vehicles, but would, for example, using the block heater daily all year be expected to significantly shorten the coolant's life?