Block heater question

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Block heater question

November 21, 2014, 08:57:39 pm

We're currently in St. Peters, MO and if you have been following the national news you know that most people are predicting major riots in the area when the Grand Jury releases their conclusions on the death of Michael Brown. Ferguson, MO is about 15 miles or so east of here. Temperatures are mostly going to be under 50 degrees. Will it hurt anything to leave the block heater on all the time?

Lest anyone worry, we DO NOT expect any rioting here, but we're also not going to wait until the rioters are right outside the door. We're monitoring local news and do have a plan to go elsewhere should it become necessary.

Re: Block heater question

Reply #1 – November 21, 2014, 09:24:00 pm

I don't think it will be a major issue to leave the block heater on as long as the temperatures stay cold. We've left the block heater on for a month at a time with temps down in the single digits night and teens day and it seems to be just as good as it ever was. I started the rig up and drove it 25 miles this last Wednesday. Had the block heater on overnight.

We leave the block heater on our Dodge pickup with a Cummins diesel just like our RV all winter and have sincd 1994. But we use that more often in the winter.

Craig

Re: Block heater question

Reply #2 – November 21, 2014, 09:58:39 pm

We would leave block heaters on constantly on plow trucks stored outside. The only heaters you have to worry about are the ones that heat the oil. Yours heats the coolant.

Keith

Re: Block heater question

Reply #3 – November 21, 2014, 10:16:47 pm

Thanks. That's pretty much what I expected, but I thought I'd better ask those who know a lot more than me.

Re: Block heater question

Reply #4 – November 22, 2014, 06:54:53 am

Just be aware you're going to use a LOT of electricity. I forgot I'd left mine on for two weeks and almost had a heart attack when I got my bill. If you're in a campground then it's only an ethical issue. I'd offer to pay.

Re: Block heater question

Reply #5 – November 22, 2014, 08:01:57 am

Why do you have to worry about heaters that heat the oil? Do the heaters get the oil hotter than the engine does?

Re: Block heater question

Reply #6 – November 22, 2014, 10:10:46 am

David, if you want the engine to be warm for starting then 24-48 hours on the block heater should be sufficient especially at 50°. 48 hrs last winter here at -18 and it started right up.

A 2000 watt heater would cost 25¢ an hour to run, probably more in most places. $6/day adds up in a hurry. They are probably not on all the time.

Roger

Re: Block heater question

Reply #7 – November 22, 2014, 10:58:34 am

If I remember correctly (NOT a safe assumption), I have a 1000W heater. Current temp is 54, so I'm guessing that the heater probably isn't running much. Temperatures are going to be all over the place for the next few days, so I'm going to leave the block heater on. No word on when the Grand Jury will release their findings, so things are still pretty peaceful here.

Re: Block heater question

Reply #8 – November 22, 2014, 11:13:39 am

I would have the heater on when ever the temp is below about 40 deg. That engine should start anytime above that. I've started our Cat at temps well below that. Your call, whatever makes you feel safe and ready. ---- Have a great day ---- Fritz

Re: Block heater question

Reply #9 – November 22, 2014, 11:17:46 am

My 6V92TA with straight 40 weight oil in it will start on one battery down to at least 42 degrees. It'll start with all three batteries when it's a lot colder than that. It's a rough start with a lot of white "smoke" unburned diesel vapors and rough running and of course it's very loud for a bit until the computer senses the engine has all cylinders firing, then it smooths out and sounds almost normal. I'm sure it's not good for the engine to start it up cold with thick oil but if ya gotta, ya gotta.

I'm still curious why you have to be careful with oil heaters. Can they heat the oil hotter than the engine does? I'm planning to install a plug type heater in the oil pan drain on my next oil change. I was considering getting the most powerful plug heater but now I'm curious and considering possibly buying the least powerful plug heater if overheating the oil is a possibility. Is there any evidence of this? The most powerful oil plug heater I've found is 300 watt.

Re: Block heater question

Reply #10 – November 22, 2014, 11:43:00 am

Concern re oil heaters is possibility of condensation inside engine, with possible corrosion, if left oh continuously. Pad based pan heaters in general preferred over stick heaters, but of course more $$$

Re: Block heater question

Reply #11 – November 22, 2014, 12:44:08 pm

Quote from: kb0zke – November 22, 2014, 10:58:34 am

... I have a 1000W heater. Current temp is 54, so I'm guessing that the heater probably isn't running much...

I've never heard of a thermostat controlled block heater on a Foretravel. I know mine runs continuously when turned on.

Re: Block heater question

Reply #12 – November 22, 2014, 01:30:17 pm

Happy to see this discussion. I found the outlet under the foot of the bed, the plug (not plugged in) and the switch for the outlet (with red light) about 3 years ago!

I figured it was for a block heater, but never bothered to test it to see if it works. Today I Plugged it in through a Kill-A-Watt meter and found it draws 11 + Amps and uses about 1,390 Watts. Will start using it; and could have the past few days in Oregon.
Dick

Re: Block heater question

Reply #13 – November 22, 2014, 01:50:49 pm

This is correct for the block heater on our coach as well. The cord is just a cord with with a grounded A/C outlet plug on one end and a threaded coupler on the engine end. The heater itself is just a simple resistance loop like the electric element on our house water heater. When we got the coach, the cable was unplugged under the bed and at the engine. Both the engine and coach ends were somewhat melted, though the engine end was so far gone that it was just a lump of stuff. I had a hard time finding the heater location on the block... I theorized at the time that the block heater must have shorted out and caused the meltdown. The A/C outlet under the bed appeared to be undamaged. I bought a new block heater and cord from Cummins... When I had the baseline service done on our coach up in Colton CA (all fluids and filters changed and a couple of misc items), I discovered to my chagrin that neither the new block heater or cord was with us

Anyway, after we got back from Texas, I cleaned the melted gunk out of the terminals at the block heater end and plugged in the new cord and was surprised and happy to find the the block heater got hot, but cord stayed relatively cool. Moral of the story, I am reluctant to just turn it on and leave it on unless the temperatures are nearing freezing and staying there. There ways of safeguarding the system though...
this site has thermocubes (discussed elsewhere on the forum), heavy duty digital timers, block heaters, oil pan heaters (including a couple of interesting magnetic models (that only work on steel oil pans, of course).
Auto Air Conditioning Parts & Heaters by Auto Cooling Solutions
Don

Quote from: JohnFitz – November 22, 2014, 12:44:08 pm

I've never heard of a thermostat controlled block heater on a Foretravel. I know mine runs continuously when turned on.

Re: Block heater question

Reply #14 – November 22, 2014, 07:14:46 pm

I turned the block heater off for now, but I'll turn it back on again before we head for bed. Supposed to be near 60 tomorrow, but then the highest temperature predicted is 43.

Re: Block heater question

Reply #15 – November 22, 2014, 07:43:24 pm

In the 40-60 degrees F range, an hour or two is PLENTY of block heater time.

Re: Block heater question

Reply #16 – November 22, 2014, 08:06:21 pm

David,

If your Detroit has the block heater up high on the thermostat housing, it will take 3X longer than the Cummins block heater. If fact, the Detroit thermostat housing location means it's not a real block heater. Some Detroits have the heater under the AC compressor to block mounting plate low on the right side of the block. They work well.

Pierce

Re: Block heater question

Reply #17 – November 22, 2014, 08:44:48 pm

Pierce, I think mine is the same as yours, about eye level on the left side as I face the engine from behind the coach.

Re: Block heater question

Reply #18 – November 23, 2014, 10:53:16 am

David,

Yes, that is the thermostat housing location for the heater.

If it's working, after about ten minutes, the crossover pipe should be quite warm to the touch. If not, check the outlet where it plugs into up high forward in the engine compartment. Pull the plug out and check for overheating. Mine failed at the connection at the block heater and the supply voltage fitting. It corroded and then overheated.

New block heaters share the same part number as the straight element CAT heaters and are available in several different wattages. Also, they are of slightly different construction so should be less prone to corrosion. I chose 1000 watts for ours. They come complete with new wires. Changing on a cold engine will minimize coolant loss.

Remember to switch heater off before cranking. At 50 degrees, one hour, 40 degrees, 2 hours at lower elevations, longer if higher. Our engines don't heat intake air like some others.

Found a NOS on eBay for under $40 delivered. Thermostat location heater is different and not interchangeable with AC compressor location.

Pierce

Re: Block heater question

Reply #19 – November 23, 2014, 01:21:54 pm

How do you know that the two cycle Detroit Diesel doesn't have an intake heater? I was attempting to verify that but I can't find any statements supporting that conclusion from Detroit Diesel or anywhere else. Why does my voltmeter go way down when I turn on my ignition key and the red lights on the dashboard come on for a few seconds if there's no intake heater or glow plugs? Also, when I attempt to start the engine before the red lights go out it just cranks and cranks but doesn't actually start until after the red lights go out. It sure seems like it's waiting for something to heat up before it can start.

Re: Block heater question

Reply #20 – November 23, 2014, 04:02:32 pm

Scott,

I'm not going to swear your engine 6V92 doesn't have an intake heater but I have never seen one on a DD in the 40 years I've been wrenching. Since no major truck or bus manufacturer used one, I would think Foretravel didn't use one either. Again, it's certainly not out of the realm of possibility, but if you have one, please take a pic! Lot's of us old guys would like to see it!

Don't know why there is such an amp draw when you turn the key either. Perhaps someone with more Fortravel experience can answer that.

TOM

Re: Block heater question

Reply #21 – November 23, 2014, 04:14:53 pm

I presume the intake heater would be underneath the supercharger where I can't see it? There should be some heavy gauge wires going to it judging by the amount the voltmeter goes down when I turn the key on. I never realized the voltage went down when the key was turned on until I modified my voltmeter to stay on all the time, even when the key is off. It's been a much more useful and informative instrument since then. I installed a single pole double throw switch so I can compare both banks of batteries with the same gauge, which is also very useful and informative, especially when boondocking. I found a two stroke Detroit Diesel forum and asked about the intake heater. Hopefully someone on there will know how to verify whether or not the 6V92TA has an intake heater.

Re: Block heater question

Reply #22 – November 23, 2014, 04:54:12 pm

The problem with heaters in the oil is the oil can be carbonized if the element gets too hot.

Keith

Re: Block heater question

Reply #23 – November 23, 2014, 06:40:12 pm

Well I have pulled my blower to inspect the intercooler (pic attached) which is directly below the blower. There is no electric heater in there and I think I can tell you why: It's a very oily space. The element would get coated with oil when the engine is running. At the next startup that element would probably catch fire or at the least smoke like crazy.
I think the voltage drop has to do with 23 year old wiring and having 30 feet of cable between the battery and the dash.

Re: Block heater question

Reply #24 – November 23, 2014, 07:38:21 pm

So why won't the engine start if I attempt to crank it before the red lights go out on the dashboard? If there's no heater what is the engine doing for that period of time? Out of curiosity I just turned my ignition key on and watched the voltmeter drop a full volt immediately. There has to be something on the other end of the 23 year old wiring that's drawing a lot of current. It's not the vacuum pump and I don't hear any fuel pump or other pumps running and it's not below 40 degrees so it can't be the heater in the air dryer and it's not the mirror defogger or anything controlled from the instrument panel. Even if it's the 23 year old wiring that still doesn't explain why the engine won't start until after the red lights go out.

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