Axis Wakeboard Boat Forum

Just an Fyi heater core is up front under steering wheel.

I disconnected the hose going to the heater core from the engine. mine is marked HEATER. on the block.
i disconnected the return on the side of the engine.
I took a compressor and got,... i think it was 1/2 in pvc plug smooth.took a drill put a hole in the end of the plug so i could slip my little crappy blower gun for my compressor from lower into the plastic cap Stuck it in the hose and blew all the water out and though the heater core..

I then took anti freeze and poured it in the hose going to the heater.. put the plastic cap which is now stuck on the compressor blower piece and put it in the hose..

I blew the antifreeze through the core until it came out the return.. It worked very well.

did the same thing for a few other hoses with a 3/4 plug.

there are apocryphal stories of people blowing out the rather fragile heater cores using a compressor, and I've always been told not to use one because they can put too much pressure on the core. That said I've found that the relatively low psi pressure of a tube pump (which many of us already have on the boat) will do the job too.

I just use my lungs. Its really not that hard to blow it out. I like the idea of the tube pump... doing that next year for sure...I was a bit winded lol.

Crusader manual says:
CAUTION: If compressed air is used to purge Heater, use no
more than 10psi. The heater core can be damaged from
excessive air pressure.

well hope the core is ok since the fit was not tight I'm pretty certain that the pressure was low enough next year ill use my tube pump..

So why was this necessary, you didn't winterize entire system with anti freeze? Cause you drained motor and exhaust but wanted antifreeze in the core due to residual water???

When I did mine, even after blowing the heater core out (with my face) I could hear water gurgling around in there, but it wouldn't come out. I just shoved a funnel into the upper heater hose and raised it up high and then poured RV/marine antifreeze in until it came out the other hose. First bit of liquid seemed diluted but the rest looked like pure antifreeze.

I have replaced one of these heater cores in my boat. They are just a small radiator. Compressed air shouldn't hurt them as long at you aren't getting them above 10psi....which is tough to do. If you have all the plugs on the engine off and doing the heater core last, you should be able to blow out all of the water and not worry about it.

thanks for the reply i wanted to make sure the core was empty then i ran antifreeze through it.. it gets really cold in buffalo ny and didn't want to risk it.