Block Heater Limits

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Block Heater Limits

October 22, 2019, 07:07:13 pm

It's getting progressively colder in the Midwest and I'm turning the block heater on more frequently in advance of travel days. Is there a downside to leaving it on 24x7 in cold weather?

Re: Block Heater Limits

Reply #1 – October 22, 2019, 07:14:02 pm

Unless you are in sub zero temperatures, you do not need overnight block heater.

Downside-- POWER consumption.

Re: Block Heater Limits

Reply #2 – October 22, 2019, 07:16:52 pm

Thanks Brett. Switch off!

Re: Block Heater Limits

Reply #3 – October 22, 2019, 07:19:16 pm

They come in several different wattages. Some are 1500 watts so you can imagine the electric bill for that much juice. Fire departments leave block heaters on 24/7 but the taxpayer foots the bill. I would check on your electrical outlet to make sure it's not getting hot or even very warm. Ours was oxidizing the copper so I changed it out to a 20 amp. Clean the plug ends too.

If your block heater is actually in the block, you could put a timer on it. Three hours should be plenty.

Don't forget to turn off the block heater before you crank the engine.

In case they burn out, it might be good to carry a spare. Easy to change on ours. Cheap too.

Pierce

Re: Block Heater Limits

Reply #4 – October 22, 2019, 08:55:14 pm

Just don't forget to turn it off before starting the engine. You can burn them out.
John M.

Re: Block Heater Limits

Reply #5 – October 23, 2019, 12:23:36 am

Three hours even in sub O temperatures should be good enough.

Re: Block Heater Limits

Reply #6 – October 23, 2019, 01:36:03 am

We used to ski and use rv's. Ether start helped in zero weather and altitude. On top of a block heater. Worked about the same.

Re: Block Heater Limits

Reply #7 – October 23, 2019, 07:46:47 am

I have a block heater switch in the back, it looks like it should light up but does not. I have no idea if it is working. Anyone know if this should light up or is it time to change the block heater?

Re: Block Heater Limits

Reply #8 – October 23, 2019, 07:57:29 am

Quote from: Farrarkc – October 23, 2019, 07:46:47 am

I have a block heater switch in the back, it looks like it should light up but does not. I have no idea if it is working. Anyone know if this should light up or is it time to change the block heater?

Yes the switch should light up in the "ON" position. Sounds like you need a new/replacement lighted switch. Should be available at most any home improvement store or off the net. The switch should light up whether it has a load on it or not.

Mike

Re: Block Heater Limits

Reply #9 – October 23, 2019, 08:58:30 am

raise the bed and make sure it is plugged in

Re: Block Heater Limits

Reply #10 – October 23, 2019, 08:59:32 am

Quote from: Caflashbob – October 23, 2019, 01:36:03 am

We used to ski and use rv's. Ether start helped in zero weather and altitude. On top of a block heater. Worked about the same.

But, ether should NOT be used on modern engines with INTAKE MANIFOLD HEATERS. Ether onto red hot wires...............not a good idea.

Re: Block Heater Limits

Reply #11 – October 23, 2019, 09:09:25 am

Quote from: Farrarkc – October 23, 2019, 07:46:47 am

I have a block heater switch in the back, it looks like it should light up but does not. I have no idea if it is working. Anyone know if this should light up or is it time to change the block heater?

There is a breaker for that switch. If that breaker was tripped you would know because your line monitor line-2 is tied in to that breaker and it would read zero. See attached picture.

You can also lift up your bed and see where it is plugged in. You can test the outlet with a voltage tester and turn the switch off and on to make sure it is working properly. If you have power and the light on the switch is not lit you can replace the switch like Mike described. No power, check your breaker. If your breaker is not tripped, you show line voltage on your monitor and you still have no power, check and/or replace the switch.

You can also test your block heater to see if it is functioning. Unplug the block heater cord from the outlet and follow it down to the engine and unplug it from the the engine. Pull it out and away from the engine. Make sure the vehicle is not running with the parking brake on and take all safety precautions when going under your coach. Set a multimeter to the "ohms" setting, then touch one probe to each of the prongs on the block heater plug and read the resistance. An ideal resistance reading will be about 20 to 30 ohms, but if there is a "0" or infinite resistance, the block heater is not functional. While you have your cord unplugged and disconnected from the block heater it would not be a bad idea to continuity test it from end to end on all of the prongs.

Hope this helps, John M

Re: Block Heater Limits

Reply #12 – October 23, 2019, 09:23:02 am

Either is the worst product you can use on an engine,would use in extreme circumstances,prolonged use can harm cylinder walls,it
starts the engine but washes all oil away.

Re: Block Heater Limits

Reply #13 – October 23, 2019, 10:03:49 am

A valuable tool to have is this:

P3 International P4460 Kill A Watt EZ Electricity Usage Monitor P3 International P4460 Kill A Watt EZ Electricity Usage Monitor - - Amazon.com

Or this one with a pigtail for easier reading:

Poniie PN2000 Plug-in Kilowatt Electricity Usage Monitor Electrical Power Consumption Watt Meter Tester w/ Extension Cord Poniie PN2000 Plug-in Kilowatt Electricity Usage Monitor Electrical Power...

Lift the bed, find the ac receptacle the block heater is plugged into, unplug it, plug in the monitor, plug the heater into the monitor, and flip the switch. The monitor will show Volts, Amps, and Watts. All should be non zero.

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Block Heater Limits

Reply #14 – October 23, 2019, 10:08:57 am

Quote

Yes the switch should light up in the "ON" position.

I think a lot of folks believe the block heater is on when that red light switch is on. As mentioned above it just indicates that the outlet is energized. That outlet takes quite a beating in that engine compartment. I eliminated mine and just wired the block heater directly.
jor

Re: Block Heater Limits

Reply #15 – October 23, 2019, 10:37:10 am

After the block heater has been on for a while, open the engine door and feel the area around it. It should be warm.

I've used ether many times on our U300 Detroit (and on our Greyhound) when dry camping in cold weather. Detroit put a spring loaded cap just for an ether spray. 110,000 miles and used 2.5 quarts on a California to Hilton Head Island, SC and back.

Pierce

Re: Block Heater Limits

Reply #16 – October 23, 2019, 10:37:44 am

The block heater on the M11 is very difficult to replace. I bought the very large wrench(45mm?) required but still couldn't break it loose in the limited space available. I took it to Cummins where the tech had to remove a number on block-mounted components until he was able to remove the block heater assembly and replace the block heater on the bench. Moral of the story--don't burn out your block heater.

Re: Block Heater Limits

Reply #17 – October 23, 2019, 10:57:20 am

Quote from: John Morales – October 23, 2019, 09:09:25 am

There is a breaker for that switch. If that breaker was tripped you would know because your line monitor line-2 is tied in to that breaker and it would read zero. See attached picture.

You can also lift up your bed and see where it is plugged in. You can test the outlet with a voltage tester and turn the switch off and on to make sure it is working properly. If you have power and the light on the switch is not lit you can replace the switch like Mike described. No power, check your breaker. If your breaker is not tripped, you show line voltage on your monitor and you still have no power, check and/or replace the switch.

You can also test your block heater to see if it is functioning. Unplug the block heater cord from the outlet and follow it down to the engine and unplug it from the the engine. Pull it out and away from the engine. Make sure the vehicle is not running with the parking brake on and take all safety precautions when going under your coach. Set a multimeter to the "ohms" setting, then touch one probe to each of the prongs on the block heater plug and read the resistance. An ideal resistance reading will be about 20 to 30 ohms, but if there is a "0" or infinite resistance, the block heater is not functional. While you have your cord unplugged and disconnected from the block heater it would not be a bad idea to continuity test it from end to end on all of the prongs.

Hope this helps, John M

John, was going to mention the breaker fact, and you not only beat me to it, but continue to school us in facts I did not know so thank you...
Makes me happy to have the aqua hot. For all its potential issues, heating the engine overnight on a cold night is a great benifit. Don't need to use the block heater!

Jor thanks for that fact of the red light only meaning that the outlet is energized, not the actual heater.
All good information for sure.
As David says, and Brett as well on my coach inspection, using Ether start is not a good idea. Not good for a very expensive engine!
Good thing about the cold, it cuts the number of bugs way down.... here in South Texas, it doesn't get cold for long, in fact rarely do we get a hard freeze, and so the bugs outnumber the people by a wide margin...

Re: Block Heater Limits

Reply #18 – October 23, 2019, 11:14:21 am

If ether is use properly it is not a problem. I am a heavy duty mechanic, retired and I have started many engines with ether.
If an engine has glow plugs or like the 8.3 Cummins which has a intake manifold manifold heater you can't use ether.
The best way as someone wrote is to turn on the block heater and reach down and see if it is warm. I've changed the block
heater on a 8.3 Cummins and it was hard to get to.

Re: Block Heater Limits

Reply #19 – October 23, 2019, 11:15:28 am

Re: Block Heater Limits

Reply #20 – October 23, 2019, 11:17:48 am

Think the intended use for the block heater is to help keep the engine warm,it will not warm the engine up when cold.

Re: Block Heater Limits

Reply #21 – October 23, 2019, 12:33:33 pm

Block heater is supposed to heat a cold motor

Re: Block Heater Limits

Reply #22 – October 23, 2019, 12:50:27 pm

Quote from: John44 – October 23, 2019, 11:17:48 am

Think the intended use for the block heater is to help keep the engine warm,it will not warm the engine up when cold.

I would not leave a block heater on overnight (to KEEP the engine warm) unless you are FAR into the below freezing temperatures.

2-3 hours before starting should do the trick.

Re: Block Heater Limits

Reply #23 – October 23, 2019, 01:01:49 pm

Quote from: John44 – October 23, 2019, 11:17:48 am

Think the intended use for the block heater is to help keep the engine warm,it will not warm the engine up when cold.

The block heater is designed to heat the engine up, no matter how cold it is, to a temperature where the heat from engine compression is enough to ignite the diesel when the injector sprays.

No, the block heater is not designed to bring the engine temperature up to normal operating temperatures, just enough to allow compression ignition to take place.

Pierce

Re: Block Heater Limits

Reply #24 – October 23, 2019, 01:06:53 pm

I was able to break the block heater loose on my M11 with a little pipe wrench. Couldn't fit anything else in there.
jor

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