diesel block heater

[Jerry/MT]

Thats an interesting theory Jerry I cant say I don't believe it anything is possible but I would still doubt it has anything to do with starting an engine with it plugged in is going to hurt the heater I have done it on diesel vehicles forever.

I have never read it not saying it isn't published just I probably had thrown the instructions away is all by that point in the install.

Mainly my point of view is based on simply there would be little if any actual flow on a cold engine where the thermostat is most likely closed even though the heater has done its job it will (probably) never get the coolant temp high enough to open the thermostat at least mine wont.

My biggest fear is driving off with the cord still attached that's what will hurt my heater more than anything and why I unplug mine first!
Until that point the coolant can move if there is a bypass like my Yanmar has but it is only a 3/8" passage I doubt that would create a cavitation scenario but thats my way of thinking.

Whether you read it or not, why would the manufacturer put a warning on the instruction sheet to not run the element with the engine running? What other mechanism could you come up with that could cause an element to fail as a result of being plugged in with the engine running?

Separation and cavitation are two different phenomenon. Both result in a reduction in heat transfer that can cause the element to fail from overheating. Separation is governed by fluid viscosity and local velocity while cavitation is governed by local fluid vapor pressure and local fluid velocity. (When the local fluid velocity results in a fluid pressure lower than the vapor pressure than a cavitaion bubble of coolant vapor forms. My irrigation pumps cavitates at throttled start up flows with water at 60ｰF. of course the pump has high tip speeds and high flow.) The hotter the coolant the easier it is to cavitate for a given bulk velocity.That's just fluid dynamics. So one can't eliminate cavitation as a source of reduced heat transfer with even relatively low bulk velocities because the problem is one of local velocities around the cylinder inself (which are greater than the bulk velocity). Regarding separation,flow separation from a cylinder in cross flow is a classical flow separtion problem. So whether it's one or the other or both, there is a potential mechanism for element failure.

Respectfully, I didn't want to start a p***ing contest over this issue. I merely wanted to offer a potential explanation for why an operating block heater could fail if left operating with the engine running.

I leave my block heater on for two hours, the timer turns it on and shuts it off and I unplug it before I start. I'm am reasonably certain I won't have an overheating failure of the element.

You may start your tractor up with your element running and for your element configuration and location and the time you leave it plugged in, it hasn't caused a problem for you yet. Good for you!

I suppose there are people that will start their tractor with the block heater operating, go off and have a cup of coffee, and come back to a fully warmed up engine with the block heater operating because they want a warm cab when they go out to work. This situation has a high probability for a element failure.

 

[Egon]

[QUOTEI can't think of where orientation of the element in the block is going to matter at all(as long as the element doesn't touch the block), but then again....][/QUOTE]

The inline hose heater on my Kubota had a defined top side. Found that out when I went to replace the one that was not working and read the instructions on the box. I now have an extra block heater.

 

[flyingcow]

NOTE: It was the Kats heater brand that said to unplug before starting engine. This is the type that is an inline on the lower rad hose.

 

[Don87]

[QUOTEI can't think of where orientation of the element in the block is going to matter at all(as long as the element doesn't touch the block), but then again....]

The inline hose heater on my Kubota had a defined top side. Found that out when I went to replace the one that was not working and read the instructions on the box. I now have an extra block heater.[/QUOTE]

I misread your original post, I was only referring to freeze plug type block heaters.

But that's good info on the inline heater, thanks for sharing the information.

 

[Egon]

But that's good info on the inline heater, thanks for sharing the information.

Oh, I forgot to mention that the instructions were read after the second heater did not work!

 

[Don87]

Oh, I forgot to mention that the instructions were read after the second heater did not work!

LMAO..........

Sounds like me, put it together, then read the instructions.........:laughing::laughing: :laughing:

 

[Car Doc]

Whether you read it or not, why would the manufacturer put a warning on the instruction sheet to not run the element with the engine running? What other mechanism could you come up with that could cause an element to fail as a result of being plugged in with the engine running?

The manufacturers instructions that say not to start the engine when plugged in are for tank and inline hose heaters btw not block (soft plug) heaters or irrigation pumps. We are talking about 2-4 different things which is about parr for the course as usual. :laughing:

Cooling system 101:
On a tractor like I already said there wouldn't be a mechanism of flow unless there was an open thermostat or a heater circuit or a big bypass circuit it isn't rocket science despite all that cut and paste dignifying going on.

A car or truck is a different story and not whats being discussed here.

Its supposed to be just a simple thermostatically controlled closed circuit cooling system and without flow your big ole long Pee acHe 'Dee argument doesn't hold any water whatsoever.

I will go about my lucky way now.