Cab Heater Modification

I was asked to repost my heater modifications and how I ran my hoses.
I don't have all my pictures as most are still on the old computer that crashed (motherboard went out) . These should show how I made up the shorter box.
Basically unbolted everything and then cut-off about 4" off the end that faces the firewall. Then reattached the end piece ( the large circle piece). I installed long 5/16" studs and drilled holes in the firewall matching them. I put some foam insulation strip around the area the circle piece would come into contact with. Then installed the unit.

I forgot to mention that I used 1" spacers on the studs to hold it square against the firewall. Then I used Silicone to seal around the openings as seen in the first picture here.
This last picture is my coolant heater. It is a "Hotstart" I bought from a member here (Derby) . They are extremely high quality ! and totally rebuildable ! He is only asking $62.00 plus shipping which is about 1/4 the cost and these are brand new units ! I plan on buying more from him. I have this unit mounted on the frame. You can see the lower radiator hose here.

Where did your primary filter go?

This is how my coolant heater is routed. Pictures one and three show on the right rear of the engine block how I removed the coolant plug and installed a shut-off valve. This goes to the coolant heater outlet.
Picture two shows where I put the starter solenoid as it was mounted on the engine where the valve is now. Picture four shows the valve I installed under the intake manifold towards the front. I needed to drill and tap it out to a larger 1/2" NPT size. This hose goes to the coolant heater inlet.

gimpyrobb said:

Where did your primary filter go?

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It's mounted by the right fuel tank, remember ? I'll take some pictures tomorrow.

Very nice work there. I've cleaned up the engine compartment space similar to that on all my trucks. Much easier to service under the hood. I cut the flange off the firewall end panel of the box and just have a gasket between that and mounting surface.

11Echo said:

Very nice work there. I've cleaned up the engine compartment space similar to that on all my trucks. Much easier to service under the hood. I cut the flange off the firewall end panel of the box and just have a gasket between that and mounting surface.

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If I ever take it off I think I too will remove the circle flange. Looks much cleaner that way.

Chris (gimpyrobb) this is where I mounted my "Primary" fuel filter. It is by the right side fuel tank.

Pictures one and two show the inlet hose for the coolant filter. Picture one hose end is after the thermostat so no coolant will flow until the engine is warm.
Pictures three and four show the coolant outlet line.
Picture five shows the cab heater inlet hose. Picture six shows the cab heater return line going to the water pump side (suction) .
Picture seven shows the coolant heater (Hotstart) intake hose.
Picture nine shows the coolant heater outlet hose into the lower end of the block.
Picture eight shows the auxiliary cab heater inlet. No hose yet as the heater is not installed. Picture six also shows where the auxiliary cab heater return line will go. This is the same hose inlet for the regular cab heater return hose. It also goes into the water pump suction side.
Picture ten is of course the cab heater. I used preformed 90 degree silicone hoses here. This is also where I installed the cab heater coolant shut-off valve.

rustystud said:

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Pictures one and two show the inlet hose for the coolant filter. Picture one hose end is after the thermostat so no coolant will flow until the engine is warm.
Pictures three and four show the coolant outlet line.
Picture five shows the cab heater inlet hose. Picture six shows the cab heater return line going to the water pump side (suction) .
Picture seven shows the coolant heater (Hotstart) intake hose.
Picture nine shows the coolant heater outlet hose into the lower end of the block.
Picture eight shows the auxiliary cab heater inlet. No hose yet as the heater is not installed. Picture six also shows where the auxiliary cab heater return line will go. This is the same hose inlet for the regular cab heater return hose. It also goes into the water pump suction side.
Picture ten is of course the cab heater. I used preformed 90 degree silicone hoses here. This is also where I installed the cab heater coolant shut-off valve.

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Thank you very much Ruststud. This should help me out. I'm going to mount my heater box on the factory bracket but will shorten it down and move it closer to the firewall. Unfortunately my deuce has a lot of stuff that I would have to move in order to mount the heater box to the firewall. I'll take some pics to show you. Some inside pics would be a great help as well if you get a chance.

Thanks again for the hose lay out, That will help. Quick question, is brass fine for the fittings or do I need to use stainless steel or another material?

rustystud said:

View attachment 609485View attachment 609486View attachment 609489View attachment 609490View attachment 609491View attachment 609492View attachment 609495View attachment 609496View attachment 609497View attachment 609498

Pictures one and two show the inlet hose for the coolant filter. Picture one hose end is after the thermostat so no coolant will flow until the engine is warm.
Pictures three and four show the coolant outlet line.
Picture five shows the cab heater inlet hose. Picture six shows the cab heater return line going to the water pump side (suction) .
Picture seven shows the coolant heater (Hotstart) intake hose.
Picture nine shows the coolant heater outlet hose into the lower end of the block.
Picture eight shows the auxiliary cab heater inlet. No hose yet as the heater is not installed. Picture six also shows where the auxiliary cab heater return line will go. This is the same hose inlet for the regular cab heater return hose. It also goes into the water pump suction side.
Picture ten is of course the cab heater. I used preformed 90 degree silicone hoses here. This is also where I installed the cab heater coolant shut-off valve.

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After looking at your pics, this is what I was thinking of doing.

1. Feeding my coolant filter at the same location you did.
2. Putting my 3/4" kats 600 watt screw heater in the same location as you coolant filter return. I know there is a lot of discussion of the effectiveness of these heaters but my truck has had no issues starting at 5-10 degrees. The heater would just be a back up even if it only takes it from 0 degrees to 30 degrees...still warmer than the outside.
3. Feed my cab heater from the same location you did on the manifold.
4. The return for both the cab heater and coolant filter would be off a T fitting at the water pump. This way both have "suction". I know this is where the cab heater return is supposed to go but would allow for maximum filtering as well.

I'll try and get pics up tonight or tomorrow of my firewall and explain my thoughts of mounting my heater.

Brass is fine. Though if you can afford stainless steel, by all means go for it !

Here's some pictures showing the hoses better. Also you asked for some inside the cab photos of the heating system. I just have this one for now. I'll take some more later.

rustystud said:

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Here's some pictures showing the hoses better. Also you asked for some inside the cab photos of the heating system. I just have this one for now. I'll take some more later.

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Thank you sir, got started on mine a bit yesterday. Nothing real extensive but got the outside air intake installed and had to move a few things so I could remove the firewall knockout and install the duct elbow that goes there. I was able to size up my heater mount. I'm going to use the normal mounting bracket but move it closer to the firewall. I'm going to shorten my heater box so it will be compact and almost as out of the way as those who mounted it on the firewall.
I ordered my fittings from McMaster carr so hopefully this weekend I'll get my fittings installed, coolant filter, block heater, and maybe even get the heater assembly itself installed. I'll take a few pics this am and load them up.

gimpyrobb said:

Where did your primary filter go?

Click to expand...

rustystud said:

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Chris (gimpyrobb) this is where I mounted my "Primary" fuel filter. It is by the right side fuel tank.

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Greg...
I kinda like that location for an additional fuel filter. I'm now thinking of adding one there just to
improve the 'quality of the fuel', as I'd not be doing the 'heater mod' (at this time anyway ).

Your thoughts? Can there be too many fuel filters on a deuce?

Here are some pics so far. Yesterday I had a couple hours before the snow started. So I installed the fresh air intake and remove the heater knockout on firewall and installed the duct elbow. I had to move my brake remote reservoir and my flasher unit as both were installed in a fashion that covered the heater knockout.

AZK9 said:

Greg...
I kinda like that location for an additional fuel filter. I'm now thinking of adding one there just to
improve the 'quality of the fuel', as I'd not be doing the 'heater mod' (at this time anyway ).

Your thoughts? Can there be too many fuel filters on a deuce?

Click to expand...

Actually there can be to many filters. You don't want to use up all your pump pressure pushing through filters. All big rigs and really most all modern diesel trucks and busses use just three fuel filters. The first is almost always a water separator/filter. The second filter (Primary) is used to catch the larger particles. The last filter (secondary) is the final and always the finest filter. Today that usually means at least 5 microns. Some of the newer pumps need a 2 micron filter like the Cummins ISL and ISB engines. I was at a rebuild class on the ISL injection pump a few years ago. Just the warmth of your hand for 10 seconds was enough to prevent the piston from being installed. Those are crazy tolerances ! One of the other mechanics, when it came his turn to assemble it actually forced in the piston. We didn't know this till later. When it came time to test it, it actually blew apart ! Cracking the housing ! The instructor was not happy ! He told this guy "will you just cost us $2000.00 !" . That also ended the class as they didn't have another pump to work on. Thankfully I was the first guy to do the rebuild and so didn't have to come back.

Here's some more pictures of my inside hoses.

Well I finally got my heater box that I modified a week or so ago mounted and installed in the engine compartment. I need to hook up the duct from the heater to the firewall elbow and source some longer intake flex hose to feed the heater box from the fresh air intake. After I'm sure that is all hooked up properly then I'll drain my cooling system down and hook up all the plumbing for my heater, coolant filter, and install block heater.

The way I mounted the box allows me to get nearly as much clearance as those who have mounted it to the firewall. All service items are easily accessible even the secondary fuel filter.


For some reason pictures are not uploading...go figure...I'll try again later.

Sorry guys, seems the issue with the pics is they are too big for some reason. Never had this issue before. Have to figure it out.