Heater core leaking?

I have got a leak in my boat and I can't figure out where it is coming from. It's not coming fromt he shaft seal, or engine. I have shut off the heater valve on the motor. The heater has an intake and return line. The valve shuts of the intake. What shuts of the return line? Could the presure from the motor be enough to push water up the return line into the heater causing it to leak? I think the heater is bad because the side of the boat next to the heater is drenched. I'm going to intall a jumper hose this week so that I can rule out the heater all together. Does anyone else have any idea's? It only leaks when under load, the fast you go the more water I get.

Your symptoms sound sort of like what happened to us. But our heat exchanger is mounted under the instrument panel near the driver where we could figure out that it leaked, once we went: duh, how come the carpet keeps getting soaked.

My heater core sprang a leak once and another time the hose kinda rotted where it was clamped to the core. You can buy a short little pipe, take the two hoses off the heater and clamp them to the pipe to bypass the core. I can't quite remember but the standard garden hose connector kit might even have worked. When the hose rotted, I just cut off a half inch or so and clamped it back on the heater - there probably is enough slack hose to do this. Used some kind of silicon stuff to really seal the connection.

I would not recommend trying to patch the core if that's where the leak is. Take the old one into an auto parts store and have them match it up with the right replacement from the catalog. I think the right core for a two hose Heatercraft is something like the core used for a 1977 Lincoln, but it could be different for yours. Cost about 55 bucks for a new one for us.

My buddy just had this happen on his '00 X-star. There is enough pressure to push water through the return line, we thought we'd be able to just plug the sending line, but still got water from the return. You can plug them both, or put in a U like Air Besar said. New heater core's are only about $70 or so.

mb

I just went through this on my '01 air nautique. Take the heater core out and go to your local auto parts store and have them match the core. My core was the same as an early ford van. The core itself was $70. I saved about that much by just replacing the core.

Thanks guys. I put s jumper hose in it last night I hope it works. I'll find out thursday when I go out.

My heater core in my '01 X-Star just 'burnt out' and it just was replaced. Problem solved.