Thread: block heater

Good question, and I don't really have a clue either.

The factory block heater on my car doesnt make any noise that I know of, though it does sit outside plugged in while I sleep haha.

FWIW, I have heard diesel block heaters in John Deere tractors and cat powered semis make a hissing sound. When I was growing up, that is how dad taught me to check to make sure it was working.

I could be way off here, but it could have something to do with the adhesive getting warm.

Originally Posted by frosty

Mine makes a hissing noise sometimes as well. The colder it is the quieter it hisses. Not sure why but I do know one thing. When I go outside tomorrow morning my scangauge is going to say 100*F even though it is below zero outside. I love my block heater

Yours must be better than mine or you keep it running all the time.

I run mine on a time delay to turn on 3ish hours before I leave in the morning if I work and that will keep it at +50 of the ambient temp outside, normally. Like this past weekend it was -10 overnight, car was +45-50 when I went to start it.

It makes it easier to start up, far easier, plus you don't need to let it running for long to have heat, as usually, as soon as you crank it up after it being block heated, you are near to have your heat.

I don't use mine unless it's colder than -10F, right now it's just -6F so it's tolerable. (Not so tolerable for us, as with the winds it's -36F right now.) When it dips bellow -30F without the winds, I usually plug it on in the night to make sure the coolant doesn't go too cold, as it's just 50/50.

Pretty much what he said. Most people in super cold climates run it to prevent the block from cracking, even a 70/30 mix of coolant will only be good down to -30 to -40 degress at the most. ( Thats the temp of the coolant itself, not the air.)


I run it so I don't have to let it idle for 10min to get heat and defrost my windows, it'll only take half the time to get hot heat with it plugged in. Aswell as making it way eaiser on the entire lower end of the engine. When the oil is so cold its harder for it to move around and its slower and does not do its job as good as it could when its warmer.

some cars came with them from the factory, others had them installed as a dealer option, and of course you can buy and install one your self. they run about 35 bucks. it replaces a freeze out plug.

The block heater on my prix makes a humming kind of noise. My diesel doesn't though. Factory heaters on both. Idk why It does it. Never really cared lol

I had to replace mine once so it might be a higher wattage. I leave it plugged in all night.