Cummins engine heater question

[fun time]

I have a Cummins 300hp ISB. I have a switch that says "engine heater" on my electrical panel that runs off of 110volt. It plugs in to a 110volt recept. Is this the same as a "grid intake heater" that comes on when the ignition key is activated? My manual says nothing about the engine heater but says I have grid heater. Here is why I am asking. Planning on heading south on Monday. Temps will be in the teens in the morning. I was going to turn on the "engine heater" the night before and leave it on all night. The Cummins dealer said I should not do that. He said turn it on for about 1/2 hour and that should be plenty. Should I leave it on all night or not? Sure would welcome your input folks. Thanks in advance.

[fun time]

I have a Cummins 300hp ISB. I have a switch that says "engine heater" on my electrical panel that runs off of 110volt. It plugs in to a 110volt recept. Is this the same as a "grid intake heater" that comes on when the ignition key is activated? My manual says nothing about the engine heater but says I have grid heater. Here is why I am asking. Planning on heading south on Monday. Temps will be in the teens in the morning. I was going to turn on the "engine heater" the night before and leave it on all night. The Cummins dealer said I should not do that. He said turn it on for about 1/2 hour and that should be plenty. Should I leave it on all night or not? Sure would welcome your input folks. Thanks in advance.

[RCtime]

It has been my experience that you can leave it plugged in as long as you want.
When the weather turned cool in So. Calif. we left the Fire engines plugged in all the time.
When we pulled out of the fire station it was pedal to the metal. Most diesel gurus would cringe at doing this, however our fire engines of all different manufacturers lasted for their 20 yr.or so planned lifetime and then went to reserve status or sold to Mexico and continued their duty.

[AFChap]

fun time

I agree with the other posters on leaving the engine heater on. I've seen some say it will do it's work in 2 to 3 hrs, but I have turned mine on the night before departure a couple of times in really cold weather.

As for your other questions, NO, the engine heater is NOT the same as the "grid intake heater." The engine heater is basically a block heater. The grind intake heater pre-heats the air going into the intake. (which is why you should NEVER use ether or similar "starting aids" sprayed into the air intake.)

[gunny]

No, the block heater, also known as the jacket water heater is not the same as the grid heater on a Cummins B.

The man at Cummins told you to run it for a half an hour or so before you started the engine for a reason, maybe a couple. The high end heaters, such as found on fire trucks or engines that are unattended have a thermostatthat shuts off when the engine reaches the set point of the thermostat, commonly they are on at 80 and off at 100 or on at 100 and off at 120. Yours probably does not have this thermostat and it will run the heater as long as it gets power. Its probably small enough so that it won't overheat the engine but that leads to the other reason, why do you want to waste electricity by running it all the time? Look at your engine and locate the heater, if it is in a freeze plug, no thermostat, if a seperate tank type heater, it does have a thermostat. The tank type heters, by the way, are notorious for failed thermostats, they'll run until they cook the coolant or melt down when the thermostat fails.
The man at Cummins told you right, follow his advice.