Big block heaters boiling & degrading coolant?

[Andrei_ierdnA]

I have a suggestion if you cannot get to the bottom of this dilemma:

* sell your large 1kW block heater and with that money buy a small block heater 125-250 W.

So instead of heating your coolant in 20 min and having a localized boiling point, you will have to plug into a timer and let it heat the coolant for several hours overnight. Same end result, same electricity cost, but with a lower and more gradual heating of the coolant and without any localized boiling.

[Daox]

Thanks for the idea Andrei. That is definitely a possible and good solution.

For me, I have in the works an electric water pump which I'll be able to turn on when I plug in the block heater. Circulating the coolant should prevent the coolant from boiling inside the heater. This will be done either way as its one of my next mods to do to the car. But, I also wanted to gather info for myself on use with other vehicles and for other ecomodders on this topic.

[oil pan 4]

I have already tried this.
A low wattage block heater uses a lot more power to reach the same temperature as the large one.

My 3500 watt coolant heater can raise the temperature of the coolant in the engine from freezing to 75'F in 20 minutes, using just over 1kwh.
To get the same effect with a 600 watt block heater you have to leave it plugged in for hours to get the same results. Any more than 2 hours and you are at 1.2kwh.
To warm the coolant by 40'F with the smaller heater it takes around 3 to 4 hours if it can even raise the temperature 40'F. That adds up to a lot more than 1kwh.
So in the case of coolant heaters more is actually less.
That is why with the suburban engine is going to have the 5500 watt coolant heater plus two 600 watt heaters. The faster you can heat the coolant the less heat you loose to your surrounding environment.

Then even if you go to a lower wattage heating element the heating elements just get smaller. So the surface of the heating element likely gets just as hot. My 400 watt coolant heater is slightly smaller than the 600 watt elements I typically use, the newer 1,000 and 1,100 watt up grade heaters are about double the size of the 600.
The only way to get a lower heating element surface temperature is get a very large heating element such as a 1000 watt 120v element and run it on a varrac and dial the wattage down to what ever you would like to see it run at.
Or get a 240 volt heater and run it at 120 volts.

[Andrei_ierdnA]

Originally Posted by oil pan 4

I have already tried this.
A low wattage block heater uses a lot more power to reach the same temperature as the large one.
...

Indeed, you are totally right. With a small heater the rate of heat gain is considerably affected by the rate of heat loss to the surrounding freezing environment, making the overall duration much longer and resulting in more electricity/power used.
The electric water pump is probably the best solution.
Doax, can you share the pump power (W)? It should be fairly low power, so negligible running costs, right?

I'm very interested in your findings about the coolant life expectancy given the localized boiling, although based on the manufacturers' responses so far, we may never know the truth.

I'm assuming anyone using a grille block will also run into a similar situation, making coolant fluid changes needed sooner than scheduled, right?

[Ryland]

Test it and find out.
You know that it turns acidic as it breaks down and I'm sure you have a few drops of fresh coolant to test to get a base number, and maybe a friends car to compare.
So go to the drug store and get a box of ph test strips.

[Daox]

Thanks for the feedback guys.

I did measure the outlet temperature this morning. Ambient temp was about 9F out. I had it plugged in for roughly 20 minutes. I could hear it boiling as I shot the picture below. But, low and behold, the outlet temp was...



I moved the IR temperature gun all around and 160F was the highest I saw.

But, I can hear it boiling! It sounds just like boiling water on a stove top, and the manual says it boils it too... So, now I'm confused haha. Any ideas?

[Daox]

Originally Posted by Andrei_ierdnA

Doax, can you share the pump power (W)? It should be fairly low power, so negligible running costs, right?

I don't have power consumption numbers yet. My next step is to put the motor in and test it. My thread on it is here:

http://ecomodder.com/forum/showthrea...eap-29896.html

I'm assuming anyone using a grille block will also run into a similar situation, making coolant fluid changes needed sooner than scheduled, right?

I disagree with this. A grill block shouldn't increase operating temperatures of the engine. The coolant temperature should still be thermostatically controlled via the thermostat. You should definitely get up to temperature quicker with a grill block, but you should not sustain higher temperatures once maximum operating temperature is reached. If you are, your grill block is too big. However, I've run full grill blocks on a couple vehicles and I've never had a problem with this. My radiator fan will kick on and cool things down even with a full grill block in place. However, if your fan was to fail you would definitely have problems.

[RedDevil]

I bet it boils like a portable electric water boiler does.

Soon after you flip the switch they start making a rumbling noise, caused by tiny bubbles of steam expanding on the heater plate and collapsing when they break loose and rise in the colder water above.
When that gets hotter the bubbles grow bigger and collapse more slowly, making the sound drop in pitch and intensity - until the bubbles reach the surface when it is done.

When you look inside a boiler when the water is still cold you can't even see the bubbles that are making all the noise; they are that small.

Your heater is operating in the same phase as a cold filled electric water heater.
Only a very small amount of coolant gets converted to steam (and back to fluid when it breaks free of the heater core).
Therefore I think degradation is not much of an issue.

[Daox]

One more reply. This guy actually seems to care:

In order to answer your question, I would need to know the approximate temperature to which the coolant is being heated. Heating the coolant above the standard operating temperature of an internal combustion engine (roughly 200°F) will cause the coolant to degrade more rapidly than it would normally. Please let me know if you require anything further.

So, I replied telling him the outlet temp is ~160F, but I can hear it boiling. I think the boiling is localized to the heating element itself.

I'll update as I get more info.

[oil pan 4]

Forced circulation will further reduce the level of hissing, crackling and popping you hear as compared to natural convection.

When I turn the electric coolant pump on in my diesel the 600w heaters get noticeably quieter.