Is my block heater working?

[fieldserviceengineer]

When checking immersion heaters with an ohm meter, two things you do not want to see: infinite resistance indicating the element is "open circuit" such as burned through the inner heating element. The other is 'zero resistance' which can be an internal short of the element wire. Heaters are constructed of an element wire that is encased in powder that isolates the element from contacting the outer sheath. This is especially important when the element is being formed in the press to make the necessary bends. As for resistance, I would not count on it being any set value such as "48 ohms". Resistance value depends on the length of the element wire. It can be anything between infinite and zero. When testing heater elements with an ohm meter, first test the two pins of the element circuit to get some reading. Also test between each pin and the housing to see if there is a short circuit. In reviewing my tech data from Kim Hotstart Mfg. on testing their immersion heaters, they do not have any specific resistance reading. It must show continuity (something between infinite resistance and greater than zero ohms). Further, they state that the element housing will become warm if it is operating.

On installation of a block heater, it is vital that the cooling system be correctly filled to avoid an air pocket around the element. On some engines, the heater is situated close to an internal wall above that can hold air around the element. When the heater starts, it goes into an internal meltdown due to insufficient coolant around the element. These elements heat the coolant by boiling the surrounding fluid. Coolants composed of high levels of antifreeze (>60%) will have a tendency to resist the convection currents (hot fluid rises, replaced by cool fluid coming in). On many of the elements that we (Fleetguard) have received back as having failed, we have found the elements to have evidence of the coolant "cooked" on the outer sheath. Also, elements can fail from buildup of mineral scale which insulates the heater leading to element burnout, as well. Avoid the use of hard water when mixing your engine coolant or buy premixed coolants formulated with demineralized water.

 

[jimmysisson]

That's a good reason for installing the heater before you REALLY need it, to let the air get out of the cooling system. The freeze plug heaters are very reliable and heat the block thoroughly.
Jim

 

[OldGeezerWNC]

Maybe my way of doing it is too simple and not techy enough. But after 40 years of working anything that was broken. I figured I was ready for the simple life. I have a Kill A Watt tester look for them at Northern or Harbor about 40$. It's a simple thing, plug it into the wall plug anything into it from your block heater to your toaster. It has buttons to check supplied voltage, amps being used as well as wattage. I like the kwh hour consumption for the time you leave it plugged in. If you are using a 700 watt heater and it shows 0 or say 213, then the heater isn't working right. Cool thing is you can watch the readout to see the time of the on and then off cycle. By the way, I've used the 300 watt mag heaters by Kats for about 30 years so far. I was right in the center of this last big storm. I still have 10 inches of snow on the ground. For 9 days it didn't get above 22 and three nights it showed 0 to 3 above in my lower barn. I pulled the battery out and moved it to by machine shop and kept it on the charger. Yesterday I was fianlly able to get to the tractor. Kubota T1900 Diesel, installed battery, block was warm to the touch at 21 degrees. GP light went out after about 25 seconds. Fired right up. Lots of people bad mouth the mag heaters. I've got about... counting..... 11 of them, I put them on the head tanks and pumps in both my pump houses (4), one on all three tractors (3), and four vehicle, My 4x4 Ford 250, wife's Volvo 850, son's PT Crusier and my 1965 Chevy farm truck (4). Some are more than 6-7 yrs old. All are Katz. I never plug them in unless they are in contact. Tried them on the cows, kept falling off and just made me hungry smelling burgers all the time. Old Geezer

 

[JB4310]

Maybe my way of doing it is too simple and not techy enough. But after 40 years of working anything that was broken. I figured I was ready for the simple life. I have a Kill A Watt tester look for them at Northern or Harbor about 40$. It's a simple thing, plug it into the wall plug anything into it from your block heater to your toaster.

Lots of people bad mouth the mag heaters. I've got about... counting..... 11 of them,

Old Geezer

The kill a watt meters are pretty handy, (you can get them at Home Depot now) just feeling the block lets you now if your block heater is at least getting warm. With the meter you'll know if it's putting out its rated wattage.
Just don't do what I did and firmly grab the metal housing of your newly installed in line radiator hose heater after it was on for 20 minutes!!! Not much question if it was working or not

I found with the hose heaters you need 2 hours minimum.

Thanks for the heads up on the mag heaters, I wondered how effective they might be. Being portable, able to stick where needed like that, I think I'll try at least one.

JB.