Adding a Hydronic Coolant Heat

cctaylor410

New member
2014 35000 LWB Ext
I picked up a D5 hydronic heater mainly for hot water (using a heat exchanger) and cabin heat in the back but I would like to tie it into the block as well for engine preheating. Also stops me from having to add an additional reservoir/expansion chamber.

However it extremely difficult to figure out where to tap into the coolant system on the engine. Does anyone have an example of this type of hook up or coolant system diagram?

I wanted to use the following coolant thermostat so the hot water and air loop is heated first:
https://www.lubricationspecialist.com/espar/6-port-combination-valve/
 

cctaylor410

New member
I was researching Webasto and this is picture of original piping for Sprinter https://allegro.pl/oferta/webasto-ogrzewanie-sprinter-crafter-a9068305800-8570201554
Looks pretty complicated and expensive, so living in warm climates I went for air heater, what sells for $110 new.
I am building stealth motorhome, so no outside vents, where I plan to use electricity for warm water.

Thanks for the tip. Maybe I can leverage that plus other diagrams I found. The direction of coolant flow is also difficult to determine. If I new where it was going and what controls it I could tap the right spots. I simply need to tap a source and return at the engine. The rest is straight forward.
 

Kajtek1

2015 3500 X long limo RV
You want to tap into hot water hose before aux coolant pump I assume. Did not research coolant heaters, but I think they have build-in circulation pump?
Sprinter has convenient place for the heater under passenger seat, but those units can be mounted anywhere and would engine warming be my primary purpose, I would simply install it under the hood.
Short hoses and lot of space.
My bus also seems to have 2nd cabin heater under the floor. I did not inspect it yet, but that might be another good spot to tap into heater hoses.
 
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cctaylor410

New member
You want to tap into hot water hose before aux coolant pump I assume. Did not research coolant heaters, but I think they have build-in circulation pump?
Sprinter has convenient place for the heater under passenger seat, but those units can be mounted anywhere and would engine warming be my primary purpose, I would simply install it under the hood.
Short hoses and lot of space.
My bus also seems to have 2nd cabin heater under the floor. I did not inspect it yet, but that might be another good spot to tap into heater hoses.
My van doesn't have any existing aux heating or hoses. I'm not to concerned about where to mount everything. That part is pretty straightforward and lots of space. It's specifically which hose to tap for the pick up and which for the return to achieve the proper circulation
 
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cctaylor410

New member
So my plan based on everything I could find it to tee the coolant line going to the EGR positioner for the pick up going to my circuit. I'll use the empty port on the H junction near the bottom of the radiator for the return from my circuit. If my assumptions are correct this should circulate coolant through the block to warm it up.
 

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johnplyler

2020 4x4
2014 35000 LWB Ext
I picked up a D5 hydronic heater mainly for hot water (using a heat exchanger) and cabin heat in the back but I would like to tie it into the block as well for engine preheating. Also stops me from having to add an additional reservoir/expansion chamber.

However it extremely difficult to figure out where to tap into the coolant system on the engine. Does anyone have an example of this type of hook up or coolant system diagram?

I wanted to use the following coolant thermostat so the hot water and air loop is heated first:
https://www.lubricationspecialist.com/espar/6-port-combination-valve/
Hi, I am about four years behind you, but I did the same thing- heating my water, air and then the engine using one continuous loop. I am using the engine's expansion tank only. I have ran it for three days, about 8 hours each and all is well so far. You can find my build and pictures under RV & Conversion Talk- Van Layout Ideas.

Just wondering if you ran into any issues? I did connect to the engine block at a different locations- going in T connect at the firewall and coming out T at the front of the engine, right where the hoses enter and leave the block.

All appears to work with maybe the exception of controlling the temperature. The Easy Start Pro does not appear to have much control over the temperature, or at least I have not figured it out yet.
 

photau01

Active member
You want to tap into hot water hose before aux coolant pump I assume. Did not research coolant heaters, but I think they have build-in circulation pump?
Sprinter has convenient place for the heater under passenger seat, but those units can be mounted anywhere and would engine warming be my primary purpose, I would simply install it under the hood.
Short hoses and lot of space.
My bus also seems to have 2nd cabin heater under the floor. I did not inspect it yet, but that might be another good spot to tap into heater hoses.
.
I am trying to install my hydronic heater in my 2023 sprinter, plenty of room. I could not quite imagine how to mount the exhaust so the fumes don’t get sucked into the air intake on the hood. Also there is so much plastic under there! The main reason for the heater is to preheat the engine, but plan to tap the start button 2x to activate the dash blower to grab some heat before crawling out of my sleeping bag.
Any ideas would be appreciated.,
 

Kajtek1

2015 3500 X long limo RV
.
I am trying to install my hydronic heater in my 2023 sprinter, plenty of room. I could not quite imagine how to mount the exhaust so the fumes don’t get sucked into the air intake on the hood. Also there is so much plastic under there! The main reason for the heater is to preheat the engine, but plan to tap the start button 2x to activate the dash blower to grab some heat before crawling out of my sleeping bag.
Any ideas would be appreciated.,
Long time since my quoted reply and now I have picture of factory H5 heater.
As you can see factory did not worry about exhaust and directed it right under the van, but then H5 heaters are not designed for long operation.

H5.jpg
 

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