Block heater time vs. temp?

Newblue · Nov 30, 2005

I have a TC45DA with a freeze plug block heater. How long should I leave the heater plugged in at different temps? It doesn't look like there is a thermostat on the heater itself. Thanks to every one for all the helpfull info on this site.

thclimer · Nov 30, 2005

In the past I’ve wondered this myself. Here has been my experience with a TC33D:

30-20 degrees – I plug my block heater in for ½ hour.
Below 20 degrees - I plug the block heater in for 1 hour.

I’d be curious to hear what others do.

hazmat · Nov 30, 2005

I don't have time to wait to clear snow in the morning before work, so If white stuff is forcast, I plug it in before bed. Engine temp guage actually reads "warm" in the morning. /forums/images/graemlins/cool.gif

MikePA · Nov 30, 2005

If white stuff is forcast, I plug it in before bed. Engine temp guage actually reads "warm" in the morning. 
I do the same thing. /forums/images/graemlins/smile.gif

thcri · Nov 30, 2005

( It doesn't look like there is a thermostat on the heater itself. )

You may not see a thermostat but I would be surprised if it didn't have some way of shutting down. Every one that I have seen on the shelf stats automatic shutdown. Some of them are done by resistance.

So having it run too long would not be a problem. But typically if you have it on for more than two hours you will cover all temperatures.

murph

db2 · Nov 30, 2005

Yah.....I agree two hours will cover every temp. I usually plug it in for 1/2 to 1 hour but if its -30 to -40 I'll let it go for an hour and a half to two hours. Most block heaters are either 750 or 1500 watts. You can also feel the engine block with your hand to get an idea how well your heater is doing it's job.

MikeD74T · Nov 30, 2005

I plug my Duramax into a switched outlet (actually a screw in on a garage outside light). I turn it on when I get up, 30-45 minutes before I leave. Gives me immediate defrost. Heated seat does the rest !!! Have found 20 minutes adequate for my Case 580 'cause I still have to wait for the hydraulics to warm after starting.

Thorndike · Nov 30, 2005

I've had quite a few deisels, all with block heaters. I've left them plugged in for a day at a time with no problems. Everything from a deisel Rabbit, 7.3 Stroker, TC35DA, 580 Case, 450 Case, and a couple bigger trucks. On another note, on all the trucks and the Rabbit, the temp gauge hardly read anything after being plugged in overnight unless the temp was above freezing. Still had to drive either one for a few miles before I got any real heat.

Just leave it plugged in all night if you want, won't hurt anything. /forums/images/graemlins/grin.gif

RickB · Nov 30, 2005

I have never seen an immersion style (frostplug) heater that had a t'stat. They simply don't make enough heat to cause problems. External tank style heaters; some do, some don't.

LRH · Nov 30, 2005

Some block heaters do have an overtemp switch built into the cord; a small metal disc that makes contact with the outer face of the heater when plugged in. Don't know why some do and some don't.