block heater

hemsteadc · October 11, 2019

2008 FL m2, Cummins 8.3L

Can I leave the engine block heater on all night?

Jaydrvr · October 11, 2019

Sure, that's the whole point. But, just like any heater, it's not inexpensive. Jay

hemsteadc · October 12, 2019

thanks.. yeah. they do draw some juice, but it'll be below freezing in the morning and the old girl sure starts easier with that.

lenp · October 12, 2019

Just plug it in an hour or two before you plan to depart. Doesn't take long to heat it up.

Lenp

Steven@146 · November 5, 2019

I am new around here but just an FYI for the Ram Cummins, when we bought our 2019 3500 here in Texas it did not have the plug in cord for the block heater. From what I read all Ram Cummins engines have the block heater installed, they just don't give you the plugin cord. For our travels up to Northern Indiana for the holidays, Instead of paying the dealership a high price for the option (which is the cord), I got one off Amazon for a few dollars and just plugged it into the block heater and ran the cord out through the grill. Works great!

And yes I usually leave it plugged in all night or if you want like he said, just plug it in an hour or so before you start it. Or don't worry about it, "Wait To Start" then turn on the seat warmers!!!

Edited November 5, 2019 by Steven@146

rpsinc · November 22, 2019

Or use a plug in timer so that it will start the heater at say, 3 in the morning. Less energy consumption and still no fuss for the need.

hemsteadc · November 26, 2019

On 11/22/2019 at 7:49 AM, rpsinc said:

Or use a plug in timer so that it will start the heater at say, 3 in the morning. Less energy consumption and still no fuss for the need.

Yeah, one with really beefy contacts! I assume these heaters have thermostats...?

Edited November 26, 2019 by hemsteadc

rpsinc · November 27, 2019

I believe they do. Another option if high current is a concern, is to use a timer as is used for lighting or sprinkler systems, that have a rotary clock and are rated for higher capacity.

GR "Scott" Cundiff · November 27, 2019

I started using the block heater on my Caterpillar C-7 motorhome before any move in which the temps are below 50. I know I don't need it, but the rig starts quicker with it. I actually have a 110v outlet in the engine bay for it so I plug in before going to bed the night before I move.

rickeieio · November 28, 2019

Block heaters are generally 1500 watts, and have no thermostat. That means they draw roughly 14 amps of 110v current as long as they're plugged in. Generally, an hour or so is sufficient to warm up a small motor like most of us are using. Keep in mind, the heater only heats the coolant, not the oil which is down in the pan.

Diesels aren't all the same in how they cold start, plus, if the starter, cables, or battery(s) aren't up to task, the motor won't spin fast enough to start when cold. I have a farm tractor that from new, needed ether to start below 40*f. After years and years, I refurbished the starter, replaced ALL the cables with larger gauge, and replaced the 2 -6v w/ 3- 12v batteries. It now starts at 20*f as if it were summer time.

Alie&Jim's Carrilite · November 28, 2019

When we were in cold climates and we were not paying for power, I always plugged the Volvo in for any temps below 40*. Since the block heater heats the coolant, which in turn flows thru the heater core, I consider it more a matter of driver comfort for those first 15-20 minutes waiting for the engine to warm enough to make some heat. Our old Cummins M-11 starts without help down to zero and below, but it sounds like an old Hit & Miss for a few seconds.... plus it takes care of any left over mosquitoes with the clouds of smoke....

hemsteadc · November 28, 2019

2 hours ago, rickeieio said:

Block heaters are generally 1500 watts, and have no thermostat.

So sans thermostat you can safely leave them overnight?

rickeieio · November 28, 2019

I have many times. It makes the electric meter go round and round.....

Even plugged in for hours, you radiator will be cold, because the thermostat prevents flow until the coolant reaches a certain temp, usually near 190*f or there abouts. That said, the warm water in the block is available for the heater core, once the water pump is spinning.

As Jim pointed out, a warm motor gets happy much quicker.

hemsteadc · November 28, 2019

1 hour ago, rickeieio said:

as Jim pointed out, a warm motor gets happy much quicker.

Yes, much easier on the batteries when starting. I don't think the intake heater even came on.I needed it to leave NM in early October when we had a cold snap. Also need to be aware of wire size of extension cord for long runs.

Edited November 28, 2019 by hemsteadc

noteven · November 29, 2019

Back in the day we were taught by Cummins and Caterpillar that the majority of engine wear occurs from cold start to about 140F coolant temp. Oil temp doesn’t matter as long as the viscosity is correct for the cold start temp so it flows throughout the engine at start up. Excessive slow “warm up” idling adds to time below 140F vs putting a light load on the engine to warm it up as fast as possible, or preheat it. That’s about all I remember.

Both my little Cummins’sz have exhaust brakes which I close after start up which warms the engine many times quicker than idling. It’s recommended by Cummins to do this.

packnrat · December 5, 2019

having lived where ice does not stay around very long. i do not have real experience with a frozen diesel motor.

but from talking with many a driver that did. a block heater would be the min for these motors. (talking about class A type diesel motors)

a simple heater pad placed on the oil pan is also a great way to have the oil up to "usable" temp. this i know is to keep the motor oil and water warm to get the motor up to running temp faster to keep ware form being a $$ problem. then there is the temp of the fuel. as it can gell above 32F. if gelled it can not be pumped into the injectors. a chem helps, but not if that cold.

this is one of the reasons why diesel motors were never turned off.

but any block heater will never get so hot as to damage the block or anything else by heat alone. the block of the motor just bleeds off the heat to the air. but if it gets too cold the freezing coolant can crack a block.

ARGO · December 5, 2019

Two comments-

1 do not expect the block heater to work in 15 mins

2 In cold climates, NEVER open both cab doors at the same time.............

noteven · December 5, 2019

A common rail type diesel with pilot injection uses so little fuel to idle the engine plus it retards the injection timing when the engine is cold to prevent “cold knocking” - that the cab heater core and fan are totally capable of cooling the idling engine down to cold wear temperatures causing rings to stick, after treatment systems to be unhappy etc. Modern diesels do not like or need excessive idling.