In order to keep the CNG regulator from freezing up, you need to route a pair of hoses from the CNG regulator to the heater core supply and return lines. In the picture to the right number 7 balloon points to the inlet. Number 8 balloon points to the outlet.

There is a foil/fiberglass insolation covering both hoses. This needs carefully cut away. Do not mutilate it as you need to re-attach it when you are done.

Unfortunately the heater core has some funky hose connections that I did not want to mess with. So I was going to have to plumb the splice tees with the hoses installed. This creates a messy problem with antifreeze spill.

I fixed that by putting a funnel under the inlet hose. Then connecting a hose to the funnel end and running it to a bucket. I then took a knife and sliced into the hose. Allowing the antifreeze to empty out.

There is not a lot of room for a clamp on the angular tee branch. To get the maximum clamping area I cut the hose on an angle to match the tee

Here are both inlet and outlet assembled. I used high pressure fuel line clamps to secure the hoses.

You want to splice in the lower line first as there will be clearance issues if you have to work under the top line.

Here the top line is spliced in and the foil/fiberglass insolation is replaced. The exhaust manifold and pipe are directly under the heater lines so the insolation is very important.

I liberally routed the hoses trying to clear any obstacles and creating a professional appearance.

Here the two lines are routed over the engine. With a slight turn they line up perfectly with the CNG regulator inlet/outlet ports. Before clamping the top hose, I bled out all the air from the system by using the top hose to fill the system.