Cabin heat taps.

[Davetowz]

86 Mercruiser 165 3.7l Looking to add cabin heat, I know where Merc says to tap in, the issue I am having is finding the fittings to splice into the hoses. Ideas? Suggestions? Wild guesses? Thanks.

 

[Bondo]

Ayuh,.... Welcome Aboard,.... Pipe thread to hose barb fittin's are pretty common,....

What's the problem,..??

 

[Davetowz]

Thought of that. Was hoping someone had made a compact Y fitting that wouldn't be as bulky. Will probably go with the multi fitting congooberation for now, maybe weld up something more streamlined later. I wish Merc had provided ports on the engine that could be tapped into instead of splicing into the hoses.

 

[Davetowz]

Found the answer. Mercruiser part # 22-862993 is a y fitting that is 2 1/4" on the ends with a 3/4 y on the side. On the closed cooling 3.7l 4 cyl the taps are in the hose from tstat housing to cooler returning to hose from intake to water circ pump inlet. Kats heaters also has t fittings available at oreillys auto parts. The merc fittings sell for about 3$ each, I will go with the Y. Heatercraft also has what they call a low idle wye fitting for the return line of thier heater add on kits, brass fitting... 50$ range. Time to add some heat to the dive boat, Lake Huron is calling loudly!

 

[alldodge]

Not a 470 guy but just a comment. Formula uses the block drain plug for the hot feed going into the heater/hot water tank.

 

[Davetowz]

Block drain plug holes are probably too small for good flow on the 470. Merc specifies in the cooling diagrams where to tap in for aux water heater, even mentions an install kit on the page. never have found info for such a kit. good idea though, didn't think of that.

 

[alldodge]

Block drain plugs on my 502 are 1/4 NPT