My engine coolant tankless hot water system

[Vannautical engineer]

If one of the coolant lines develop a leak, lets say a large leak, how do you stop the coolant from escaping the engine?

The same way you stop coolant from escaping the engine if any of your other engine coolant lines leak. You fix the leak.

And to start with, you use high quality coolant lines, route them away from sources of heat and abrasion, and secure them well to the vehicle.

Just like tx2sturgis linked to, there are professional systems that require the exact same kind of extended coolant line routing for them to work. It's not doomed to fail if you properly route your coolant lines. And if they leak, then shame on me for not routing them well enough.

 

[tx2sturgis]

I totally agree with you if you have the space to install one of these units. But being in a Transit Connect, I definitely did not. 

Ah...Transit Connect....kinda small.. I didnt see that vehicle mentioned as I skimmed thru the thread, only saw mention of a 'van'...so anyway, carry on.

But, others reading this thread might benefit from the info in my post. Motor-Aid water heaters have been in use in some models of RVs for many years. Extending coolant lines, if done properly, should not result in any problems. It's done all the time in some buses and some extended passenger vans, for rear area heating units.

Again, the DIY approach is just another way to 'skin a cat'!

 

[Weight]

So much easier to have two small inexpensive valves. Valves located at the engine end of both the coolant feed and return. But you have way over complicated a simple system from the get-go. We are "cheaprvliving.com"

 

[Vannautical engineer]

Ah...Transit Connect....kinda small.. I didnt see that vehicle mentioned as I skimmed thru the thread, only saw mention of a 'van'...so anyway, carry on.

But, others reading this thread might benefit from the info in my post. Motor-Aid water heaters have been in use in some models of RVs for many years. Routing heater lines if done properly should not result in any problems. It's done all the time in some buses and some extended passenger vans, for rear area heating units.

Again, the DIY approach is just another way to 'skin a cat'!

Yeah I think going the route of buying the units you linked to is a fine approach if you have the space for it. I definitely did not. My way of doing it is a lot better for limited space. I already installed a 16 gallon fresh water tank in the van, and with everything else I have in there, there was just no way to put in a unit like that.

Also it's worth noting that doing it my way and heating up the water on demand, my engine can be completely cold, and I only have to run the engine for 5-10 minutes to be able to have enough heat in the system to have a decent amount of hot water for a shower. With these systems that run a separate tank specifically for hot water, I think you'd have to run the engine for a while to heat up all 6+ gallons in the hot water tank. And I guess that's why they have a gas burner for a secondary heat source. But again, I did not want to find a place to store a propane tank.
So yeah, at the end of the day this is the only thing I know of that could give me hot water while taking up basically zero space inside the rig for a water heater unit or a propane tank.

 

[Vannautical engineer]

So much easier to have two small inexpensive valves. Valves located at the engine end of both the coolant feed and return. But you have way over complicated a simple system from the get-go. We are "cheaprvliving.com"

My coolant return meets back up with the heater core return feed far back at the rear of my engine, buried underneath wiring harnesses and other stuff. Good luck fitting a shutoff valve in there, and accessing it if you need to. And it would have to contend with a lot of heat from the exhaust.

At the end of the day, why engineer with the expectation of failures? Maybe if this was a critical system on an airplane, but it's not. Just route the lines where they will not leak, and make solid connections. If you are putting in a bunch of shutoff valves in the lines, to me that says that you should have spent more time ensuring the lines themselves aren't going to be prone to failure or leaks.

 

[PlethoraOfGuns]

Those Motor-Aid units are pretty cool! Never knew they existed. I opted not to go propane, so I got a similar water heater for a boat. Heats using engine coolant or 120v.

And a leak is a leak. Run things proper, won't be a problem. There are many vehicle with a front and rear heater core for cab heat. Those coolant lines are just fine.