engine block heater operation question
 

Does any one know how warm the block heater will get the engine coolant? Will it reach a certain temp. and stay there? Or does it always stay on and never stop heating? I have a weak coolant percentage on a truck I am currently not driving and did not realize it. I want to leave it plugged in for about three days until the outside temp. stays above 0 degrees. Just wondering what the block heater does.

A block heater is not thermostatically controlled, you plug it in and it just heats the coolant around it, it does not circulate the coolant although you can buy heaters that do but they are an inline heater that go into a heater hose.

I read some where it uses 750 watts. I am assuming it is always on and never turns off? What about the people who leave there truck plugged in all the time even when they are not using it?

I park in a heated garage at home but when I worked I always plugged in from late fall to spring and when we went on vacation or to work somewhere else I plugged in at the airport sometimes for weeks on end, never had a problem. I think block heaters are limited at 750 watts so 2 vehicles can be plugged into a single outlet and not pop the breaker.

It is a 750w heating element inserted into the water jacket in the engine block, which is a ~900 lb chunk of iron. Depending on outside temps it should keep the block warm (80-120°f), wont overheat anything.

Anything more than 3 hours before starting is a waste and your just heating the atmosphere as the block will reach as much heat as it will hold from the 750watt heater ,use a quality outdoor timer rated for 15amps and
be sure you are plugging into a working GFI receptacle .

It would be cheaper to fix the coolant strength and not worry about it than leaving the block heater plugged in, or forgetting to next cold spell, or the power going out, or the breaker tripping, or rodents chewing thru the cord, etc.etc.etc.....[roll]