Adding coolant loops


If you've added to your cooling system, what connectors, hose, tubing etc did you use?

I've added a coolant filter and have a plate heat exchanger to go in. I used heater hose and brass barbed fittings.

Considering some hardline for neater packaging. Rigid copper pipe with soldered fittings is probably the next easiest. I'm not a pro plumber but I can sweat copper without issue or concern of leaks in a static application but in a moving, twisting, bouncing van I'd rather have fewer joints. This leads me to soft copper bent to shape. Fewer joints but not none. Soft copper coils are considerably more expensive than a stick and some fittings.



I extended from my cooling system (2016 Mercedes Sprinter) to heat my heat exchanger for hot water while driving with thermostatic valve to allow it to pass if above 160F or return without going to the heat exchanger if below that. Works great, always hot water after driving for 15 mins. No leaks or issues. I did install isolation valves at connection with engine. Used 3/4" stainless coolant rated valves and then silicon tubing with plastic barbed fittings, all rated for coolant and at least 250F. Pretty similar or better than OEM parts, and flexible tubing is way easy to install and run and don't really need to insulate it.


Engineer In Residence
Gates and dayton both have coolant rated plastic fittings. Then used heater hose (Gates etc). Most plastic fittings from big box stores are not able to handle the high temps of coolant systems.

Copper can stress crack, so it needs good support, and no repeat bending.


Yes, one should check the ratings for use with coolant and temps that engine operates in plus a safety factor. The fittings I used were all rated for this use. McMaster Carr and other supplies provide good information on use and ratings to help select appropriate materials.

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