Block Heater

Topic: Block Heater (Read 1402 times) previous topic - next topic

Block Heater

October 18, 2017, 08:25:47 am

Yesterday morning I arrived to my destination, checked power at pedestal, everything checked out ok. I plugged in and I noticed the Power Line Monitor Line 2 reading "00". At first I thought I lost one leg at the pedestal, but everything was still good. Pulled the Power Line Monitor and plugged each line into a good source at pedestal, everything works. Checked power at the monitor outlets and nothing on line 2. Reinstalled Monitor. I checked the Main breaker, looks ok. I still turned it off and reset and "00" on Power Line. I was beginning to think that the problem was in my ATS, but everything seemed to be functioning. Still stumped I began looking at all of my breakers on both the Sub and Main panel and I noticed the breaker on the Block Heater Tripped. I reset it, my wife said the numbers on PLM would go up and then back to "00" and I noticed the BH breaker trip. I turned off the BH switch, reset breaker and PLM stays on, doing what it's suppose to do. I know the BH is bad. The only thing I can think of is that the PLM L2 outlet is tied into the BH circuit breaker. Glad everything is back to normal. I will still have to look for my schematic and verify.

Questions:
1. Does anyone have a procedure for replacing the block heater?
2. Does anyone have the part number or a place to purchase the heater? Link on BeamAlarm for my
BH does not work.
3. Reading the forum I read where Pierce stated not to run BH with engine running. Just curious of
what exactly is the running engine doing to the BH? How is it affecting it? The night before I
turned on the BH and forgot to turn it off in the morning before starting the engine. I will have to
make a Warning tag for the cockpit to remind me to turn it off before starting. The switch is hidden
and easy to forget.
4. Does the engine pre-heat circulation pump need to be turned off also before starting the engine?
What happens in this scenario?

Sorry for the long winded post.

Thanks for the help,
John M.

Re: Block Heater

Reply #1 – October 18, 2017, 09:02:14 am

John,

Start by just unplugging the block heater from the outlet (access from under bed). What happens then after you reset the breaker?

Re: Block Heater

Reply #2 – October 18, 2017, 09:10:24 am

1. The block heater is immersed in the engine coolant, so when you remove it from the block you will lose some coolant. Best procedure would be to wait until "coolant replacement time", then replace the heater while the block is drained. I did read on the Forum a post where someone had a heater replaced, either at FOT or MOT, don't remember. Anyway, the tech pulled the old heater out and slapped the new one in without draining the coolant. If it is done fast, it would be messy but might only lose a couple quarts of coolant. Would require skill and planning (and luck).

2. Call Cummins shop, tell them your engine serial number, ask for block heater part number. Or register with the new Cummins Parts Online and find out the same information. Once you have a good part number, do a Google search for the best price.

Genuine Cummins Parts

https://www.cumminsfiltration.com/sites/default/files/pdf_archive/pdfs/product_lit/americas_brochures/MB12-00-4.pdf

3. If you run the engine while the block heater is activated, it is supposedly possible for the heater element to become momentarily "uncovered" by coolant, and possibly overheat and burn out. Seems pretty unlikely to me...but what do I know?

4. Don't know anything about AquaHot engine preheat procedures.

Re: Block Heater

Reply #3 – October 18, 2017, 09:23:49 am

"If you run the engine while the block heater is activated, it is supposedly possible for the heater element to become momentarily "uncovered" by coolant, and possibly overheat and burn out. Seems pretty unlikely to me...but what do I know?" When our engine problem started in January, it began with a coolant leak. The block heater was on, so it ended up uncovered, and it was dead when the tech started tearing into it.

Re: Block Heater

Reply #4 – October 18, 2017, 09:25:41 am

Like Brett says. Unplug the heater from the outlet.
When I went to replace our engine compartment insulation I had to unplug the block heater. I found one blade of the male plug burnt right off! Found part of the blade later, under the coach. Everything was melted. Plug rubber housing and the outlet on the wall. Absolutely amazing the coach didn't catch fire. I had no idea how long things had been that way. I had been turning the block heater switch on and off for two or three years before I discovered the burnt parts.
I posted the recommendation that owners periodically pull the plug and clean the blades so there is good contact.

Re: Block Heater

Reply #5 – October 18, 2017, 09:30:34 am

Quote from: kb0zke – October 18, 2017, 09:23:49 am

When our engine problem started in January, it began with a coolant leak. The block heater was on, so it ended up uncovered, and it was dead when the tech started tearing into it.

Sure, if you have a coolant leak and enough coolant runs out to uncover the heater...then I could understand the heater burning out. But in normal operations, with the block and cooling system full of coolant, I don't see how the heater could become "uncovered" long enough to burn out.

Re: Block Heater

Reply #6 – October 18, 2017, 09:47:10 am

Quote from: John Morales – October 18, 2017, 08:25:47 am

Questions:
1. Does anyone have a procedure for replacing the block heater?
2. Does anyone have the part number or a place to purchase the heater? Link on BeamAlarm for my
BH does not work.
Thanks for the help,
John M.

Howdy John, Link to p/n for my coach. MOT installed a few years ago.
Part Number Collection
Part Number Collection
Good Luck, Dave A

Re: Block Heater

Reply #7 – October 18, 2017, 11:38:29 am

Quote from: John Morales – October 18, 2017, 08:25:47 am

The only thing I can think of is that the PLM L2 outlet is tied into the BH circuit breaker. Glad everything is back to normal. I will still have to look for my schematic and verify.

John,

According to my 110 V. Electrical Diagram, A-2700.03, Page 1 of 2, 04/29/99:

Circuit #9 is on Leg 2 and provides power to the "Engine Heater" and the "Power Watch." The circuit breaker is listed with a load of 12.5 amps. The Engine Heater is shown as connected to a 110 V. Duplex circuit drawing 12.5 amps. The Power Watch is shown as connected to a 110 V. Duplex circuit with no separate amperage rating.

Hope this helps.

BTW, I thought the engine heater was to provide heat to assist starting the engine in cold weather. Why would it be left on once the engine is started? Just curious; I don't think mine is even plugged in anymore.

Trent

Re: Block Heater

Reply #8 – October 18, 2017, 11:48:14 am

I turn my Aqua hot eng pre heater off before starting. I suppose if the circulating pump flow is the opposite of the eng pump flow there might be an issue of cavatation or burning the AH pump out.

Re: Block Heater

Reply #9 – October 18, 2017, 11:51:32 am

Check and replace the block heater 110V outlet with a 20A. Block heaters are available in several different wattages so don't install one larger than the outlet can handle. Even one close to the maximum will heat the outlet and plug.

Yes, all the block heater manufacturers recommend turning off the heater before cranking the engine. Uncovering the element long enough for it to burn out does seem unlikely but also can depend where the block heater is installed. On a 6V-92TA, Foretravel installed the block heater in an extremely poor location away from the block and up high where it could see some air during cranking. The correct position is down low on the block under the AC compressor mount where Detroit mounts most all block heaters. This location is unlikely to see any air since it's at the bottom of the block.

Pierce

Re: Block Heater

Reply #10 – October 18, 2017, 12:01:35 pm

Our switch is located close to the floor at the foot of the bed.
In order to prevent accidentally flipping the switch to ON, get one of those 1/2 circle conduit clamps with the screw pad on each end. Bend it just enough to match the switch cover screw holes. Now you can still reach in and toggle the switch to the ON position but no accidental actuation. You will still be able to see if the toggle is red or not. And the darn conduit clamp won't cost even a buck!

Re: Block Heater

Reply #11 – October 18, 2017, 03:29:39 pm

John, I have a different engine than you but my bock heater shorted out earlier this spring. I found a replacement on Amazon. I had Tennessee RV install it as I didn't want to deal with the coolant issue. It was a quick job and I loss less than a quart of coolant, easily replaced.

I was amazed at how small these are compared to the size of the engine. No wonder I was told to turn it on the night before you need it. :+)

It really does make a huge difference starting it up on a cold/cool morning. Mine shares the bed switch with a battery charger. I just plug it in when I need it and don't use it at all during the warmer months.

Amazon.com: diesel engine block heater

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

Re: Block Heater

Reply #12 – October 18, 2017, 06:13:01 pm

Quote from: Jeff & Sandy – October 18, 2017, 03:29:39 pm

I was amazed at how small these are compared to the size of the engine. No wonder I was told to turn it on the night before you need it. :+)

You only have to turn it on the night before because it's not a block heater but a thermostat housing heater and not located on the block.

Take the time to pull the AC compressor and install the proper heater in that location. You will only need the heater for a hour or so. You will lose a lot more coolant at this location but then it will be a real block heater. You will also have to install short stand offs to space the compressor mount a quarter/half inch or so away to give the cord room to fit. This is the same part for all 92 series: Engine Block Heater fits Detroit Diesel Silver Series 8V-92 with ... | eBay

All blocks with an AC compressor should have the opening here. The 71 series had an block heater mount on the bottom of the block on the other side but the 92 series does not.

Alternative is to install a remote heater with integral pump. Just pull block plugs and install fittings to allow coolant to circulate from one side of the block to the other. Super deal here at $17 plus $14 shipping: Zerostart NOS Therm-O-Pump Engine Heater 810-0101 Block Heater 1000 Watts...

I did a overnight test with an IR gun and the the thermostat housing heater does not raise the block temperature very much.

Pierce

Re: Block Heater

Reply #13 – October 18, 2017, 06:45:20 pm

As always, thank you Pierce. I will definitely look into this.

Re: Block Heater

Reply #14 – October 18, 2017, 06:58:31 pm

Quote from: Jeff & Sandy – October 18, 2017, 06:45:20 pm

As always, thank you Pierce. I will definitely look into this.

The Wanderlodge people have an excellent forum and since so many of their coaches have Detroits, they are a good source of information. Here is one of their posts with the AC compressor block heater mentioned a little ways down the page: 89' WB block heater - Wanderlodge Owners Group Easy to sign up and ask questions.

One of the members comments on his crossover pipe getting warm. If the crossover pipe is warm or hot when you touch it, the block heater is in the wrong location. He also mentions having to leave it on all night.

Pierce

Re: Block Heater

Reply #15 – October 18, 2017, 07:48:18 pm

I have never used our block heater. Are you in that cold of a place to need it?

Versus the block heater the engine heat loop off the aqua hot would be my go to heat source.

If needed at all.

Re: Block Heater

Reply #16 – October 18, 2017, 09:34:14 pm

Bob,
It was in the low 40's so I fired it up the night before. I also use the Aqua Hot engine preheat also, but this one time the Block heater failed. I will wait till I get to Florida to have the Block Heater changed along with the antifreeze. I want to flush my system out and replace the antifreeze. I can live without it for now and use the Aqua Hot.
John M.

Re: Block Heater

Reply #17 – October 18, 2017, 10:02:44 pm

John,

DO unplug it. That will both confirm that the block heater is the culprit (if everything continues to work), but will also keep an inadvertent turning on of the switch from causing further issues.

Re: Block Heater

Reply #18 – October 18, 2017, 10:55:57 pm

We have a 3126 Cat. I find even in sub zero weather, the block heater hinders cold staring. Why you say? If I run the block heater for any period of time, it warm's the engine to the point that the 'Wait to start" light doesn't come on. That light is the plenum heater activating.
Without the plenum heater activated, If I can get the engine started it is a miracle. Without the block heater it is easier to start after cycling the key for a few wait to start cycles. The computer also won't allow throttle function till the engine reaches about 100 degree's, then it's response is pretty slow till the engine gets to full op temp. I have tried all different ways. Even leaving the block heater on for days. It only makes it worse.
Chris

Re: Block Heater

Reply #19 – October 19, 2017, 02:14:01 am

M11's do not have heated plenums. Block heater, aqua hot loop, ether start that can work below 50 degrees f

Up to 60 seconds crank time on a 3208 was not unheard of at altitude and below zero weather.

Done it many times skiiing. Same thing with 8.2 Detroit's

Combo of long crank and ether normally started things finally. Large cloud of cold start white smoke.

Re: Block Heater

Reply #20 – October 19, 2017, 10:09:46 am

Brett,
I did unplug the Block Heater and turned on the switch again. Everything checks out ok. We just have to replace the Block Heater. I am going to get the engine flushed out and the antifreeze replaced at that time I will have them change the Block Heater. I would like to change the antifreeze myself but it is so much liquid to dispose of and then it has to be flushed out a few times. I will just take it to a Cummins shop.
John M.

Re: Block Heater

Reply #21 – October 19, 2017, 06:00:51 pm

We bought our coach from the original owner in CA. They bought it there and it was in CA until we bought it. It did not have a block heater. The AH Preheat works very well. About three hours when outside temps are around 32°and the engine starts up with a coolant temp about 105°. I turn it off before starting.

I wondered if coaches delivered in CA came w/o a block heater of if this was a one of a kind. I don't think it was removed. The switch and outlet are there, make a great place to connect a start battery maintenance charger.

Re: Block Heater

Reply #22 – October 19, 2017, 06:48:27 pm

I was wondering about that, taking out the Block Heater and plugging the spot. Wondering if they make a plug for that. I can go for just using the Aqua Hot. I will search for it on the internet and see what I find.
John M.

Re: Block Heater

Reply #23 – October 19, 2017, 07:00:25 pm

Quote from: Caflashbob – October 19, 2017, 02:14:01 am

Combo of long crank and ether normally started things finally. Large cloud of cold start white smoke.

We had just bought this one and were up in Flagstaff, AZ @ 7k. It was around 18 degrees when I fired-up. She started right now, yes. white smoke, no long crank, no ether. Later, thanks to Brett, I learned we had a block heater which he guided me through operation..No plans to be at 18 degrees in the near future!

Re: Block Heater

Reply #24 – October 19, 2017, 07:09:48 pm

John, if it is cool out, maybe mid 40s or lower, I just turn on the AH engine preheat in the morning when we are departing. If we are using heat then sharing some if it with the engine seems like a good idea. It makes starting easier on everything.

The opposite works too, while driving the engine heats the AH and all of that heat can heat the interior while driving. Set the thermostat to 75 or so to prevent the dash heat from making it think it is warm enough. Nice to arrive somewhere and have the entire coach warm.

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