water spraying from heat exchanger end cap

[skiMachine]

Hopefully someone can help me out here... I'm new to boat ownership and maintenance (but learning oh so quickly). <br /><br />I've got a '84 Mercruiser 3.7L 170HP (I've heard some people call this a 470...I dunno) and I just started it for the first time this Spring. It started fine and I was going to let it warm up so I could drain and change the oil, but then I noticed a lot of water pouring out of the drain hole at stern. <br /><br />I peeked under the cover and saw a lot of water spraying from around the rear end cap of the heat exchanger, so I shut the motor down immediately. I've started it once or twice since then just momentarily to verify that is the place where it's leaking from. <br /><br />My question is what do I need to do to fix it? It looks like a nut on the end, which makes me think it's removable and individually replaceable. Is that possible, or do I need to replace the entire exchanger?<br /><br />For a bit of history, I got this boat before the winter last year and a friend told me that since it's a closed cooling system, I didn't need to do any draining. I've since bought a service manual and learned that there were two drain plugs on the exchanger that I should've opened. Could this have done the damage? <br /><br />...hoping to get the boat wet this month. Thanks in advance!

 

[rodbolt]

Re: water spraying from heat exchanger end cap

yep<br /> froze and broke<br /> were it mine I would remove it or at least pressure test it in place. the endcaps and gaskets are replacable. usually the motor and engine cooling side has an ethtylene glycol mix and wont freeze in this area. but the seawater side will. with luck it just warped the end cap and a cap and gasket will cure it. with no luck its damaged a cooling tube. usually if a cooling tube is damaged it will drain the engine coolant. hopefully its just an end cap and gasket. some heat exchangers had a cap and gasket at both ends. the oil change should have been done before storing.

 

[trog100]

Re: water spraying from heat exchanger end cap

your friend gave u some very bad advice indeed.. u cant even take it for granted that the engine side has antifreeze in it unless u put it there yourself.. hopefully it has else your possible problems get bigger..<br /><br />trog100