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 long/tall limo RV 2.1l
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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