Alternative Cab Heater Opions / Options

[joesco]

I would like to reach out to other members who have replaced the OEM Cab Heater / Defroster with an aftermarket 24v unit. I have seen a few online, but don't want to reinvent the 5 ton wheel.

Thanks very much!

 

[74M35A2]

Not an answer to your questions, but I am changing mine in two ways due to poor heat (M925A2) and wanting the cab warm in MI winters:

1. Relocating the entire heater core box+fan to under the seat. I converted to two group 31 batteries specifically for this reason. This way, the heater can recirculate warm air and further heat it, rather than always sucking in cold air. May not help defog, but that is addressed below in item #2:

2. In the opening left by relocation of #1 above, I am installing the arctic heater option, which is a 30,000BTU fuel fired heater. Want this for instant on heat. An efficient diesel takes forever to warm up at idle with no load, and I want to be able to jump in, fire it up, have heat going, and drive. With these heaters, if they are working, they produce heat as soon as they light off. You can even be heating the cab before the engine is even started, all without being plugged into anything. Anybody that has or uses one says you have to roll the windows down in January to control the heat, even with the heater on low. I want that kind of heat. Like to drive with coat off, want the kids to stay warm (2 girls), etc....

I did have a heater core that was mineral laden. It flowed ok, but would not transfer heat to the tubes/fins. WildChild467 figured it out and replaced it with another used but clean heater core (thanks patracy for selling it to him), and the heat output greatly improved for the truck. I'm still impatient though, if something can be had instantly vs waiting, I want it, so I am still doing the conversion. He has his heater tunnel completely inside and under his dash (M35A2), so it is re-breathing warm air, and it gets very toasty in his truck. LDT/S 465 engine is not as efficient as the 6CTA8.3, so it may be pushing more BTU into the coolant also, to note.

If this is for your M931 in your signature line, that NHC 250 probably takes forever to warm up from cold idle with no load. Ugh.....

What are you expecting to gain by an aftermarket 24V unit over what the truck has now? Probably a good place to start....

 

[DaveP]

I threw the original heater in my M819 under the map box and have plenty of heat even on the -0 days. it does have a hard top that helps a lot also.

 

[joesco]

Thanks for the suggestions. Just think no matter how well you protect the heater core inside that huge inefficient heater assembly, itit going to be problematic.

 

[74M35A2]

Thanks for the suggestions. Just think no matter how well you protect the heater core inside that huge inefficient heater assembly, itit going to be problematic.

I think so. You have a perfect storm working against you.

1. Diesel engines don't generate nearly the same amount of heat as a gasoline engine.

2. The heater is always breathing in outside air.

3. The heater core box is steel and located outside.

If I was going to leave mine under the hood, I would cover it in insulations/insulating panels. Supposedly an S-10 heater core fits closely if you wanted to try stuffing a new core in there. My core had mineral buildup which could not be seen and just changing it for another used one made a big difference.

 

[joesco]

Thanks again, just priced them online and for $40.00 shipped it may be an alternative. I am wondering if the hose connection holes in the core enclosure would need modification?

 

[74M35A2]

Rock auto probably has it for even half of that, I have good luck with them. Do a search here, a couple have done it and show the mods needed to the box, it is minor and easy to do. The core doesn't fit exactly, and one side needs to be slightly built up with adhesive backed weather strip or whatever. The threads indicate which model number core to acquire.

The core box is so big and the cores so low cost, I was thinking about stuffing 2-3 of them in there in an attempt to get the outlet temp up even higher. I may still do that when I stuff it under the seat, but it would further lower velocity which is weak to begin with.

Good luck, post your before/after pics and data if you can (measured heater temp vs engine temp vs outdoor temp).

 

[Jayco36REQS]

I've got a 24v heater core that can heat the air until the engine heats up. I put one in my truck when my original core sprung a leak. Works like a champ for instant heat to clear the windows, and once the engine heats up it will keep the cab warm even on the coldest days.

 

[JohnnyBM931A2]

Also interested in better heat for my M931A2. I have a hard top, so that's something. But I don't think it will help too much. Up here in Northern Illinois it can get to be 30 below with wind chill during the Winter, so I need to have reliable heat.

 

[JohnnyBM931A2]

What about something like these? Seems like they have good output.. the first one would probably be sufficient, and the price is excellent. Second one has more than twice the heat output, but is also more than two times as expensive.

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Question is, how do these work? Do I have to hook them up to the cooling system, or can I use it as an electric heater only? I'm a little confused by the hose connections coming off of the side..

 

[74M35A2]

What about something like these? (sorry for posting eBay links.) Seems like they have good output.. the first one would probably be sufficient, and the price is excellent. Second one has more than twice the heat output, but is also more than two times as expensive.

Question is, how do these work? Do I have to hook them up to the cooling system, or can I use it as an electric heater only? I'm a little confused by the hose connections coming off of the side..

You should remove the live eBay links very quickly. If a moderator does it for you before you do, they will likely give you a 30 day ban from the board or so. They really don't warn about them. The action will probably happen in less than an hour from your post.

The hose connections on those are for engine coolant, and the wires are only for the fan blower motor in them. Rated at 12,500BTU or so (first link), the heater in our trucks is supposedly 30,000BTU. It is just a small version of what we already have. There is no electric heater in them.

 

[joesco]

I may consider the first option, but need to explore the S10 core first.

 

[JohnnyBM931A2]

Well.. If the one's I mentioned aren't strictly electric, then I guess they are out for me. How about a 24v to 120v inverter running a standard indoor house heater?

 

[Mhartle]

Hey Guys, hope you don't mind me hoping on here. I have a HMMWV and I'm looking to add an additional heater. Can you make a recommendation? I have the arctic kit installed with the doors, roof and back curtain but now I'm looking for an additional heater. I'm searching around on line and am just not sure about what i'm seeing. Any help would be much appreciated.

best,

-m

 

[joesco]

I think so. You have a perfect storm working against you.

1. Diesel engines don't generate nearly the same amount of heat as a gasoline engine.

2. The heater is always breathing in outside air.

3. The heater core box is steel and located outside.

If I was going to leave mine under the hood, I would cover it in insulations/insulating panels. Supposedly an S-10 heater core fits closely if you wanted to try stuffing a new core in there. My core had mineral buildup which could not be seen and just changing it for another used one made a big difference.

Can a member please post either a thread or part number for the S10 heater core alternative? Thanks very much.

 

[74M35A2]

398010 is supposedly the number in the automotive aftermarket. Slight modification required, so do a search and check the detail of what you would need to do to get it to work, looks easy though. People have pics and results posted. I just woke up and not energetic enough yet to find the threads on it. Just type in S10 heater core in the search bar here. It is about $20 new and is aluminum.

Feeling a little more generous: http://www.steelsoldiers.com/showthread.php?115488-m939-Heater-Core/page5

It was a thread you were actively posting in. What happened to the CH124 heater core you had the shop install in March of this year? Looks like you have multiple vehicles, so maybe you are looking for a lower cost option than what you paid earlier, or for a different vehicle?

 

[joesco]

If you are referring to mine, the new core started leaking last week. I'm calling the shop this week as he said I had a one year warranty. I thought I "cushioned" it adequately, but it's an awful core enclosure design subject to lots of engine vibration and road bumping around! Thanks!

 

[jarhead1086]

I just installed this blower unit in the cab to replace the old core and blower in the engine area. Now I suck air from the cab and recirculate. This unit had two hook ups versus three on the old box so I sent both the windshields. 3 fan settings, 24 vdc. and it has plenty of CFM. This core is the same size as the old core. I will test it out in some cooler weather soon. It doesn't get super cold in Utah. I just want to keep my windshield clear. More leg room for my boys on the passenger side and nothing in the way of the turbo.

 

[joesco]

Very nice job, thanks for the input. Could you post or pm the specs on this heater. Thank you!

 

[joesco]

New heater arrived today. Hope to install it over the next couple of days. I work slow! The radiator shop is repairing the OEM heater core at no charge. Hope to sell the entire OEM unit and recoup some of the new heater's cost. Will post the installation pics.