leaking coolinat out of my lower unit

[snyman]

Hello guys im new the iboats and to boating. I bought a 1983 sea sprite with a 470 mercrusier i/o not sure what the outboard is. but i got cooliantl leaking out of my lower unit were the water should be going in any ideas please

 

[marinemech1]

Re: leaking coolinat out of my lower unit

Heat exchanger is likely culprit (cracked internally). Wait for Don S. too come along he sounds good on Merc stuff.
Wayne

 

[snyman]

Re: leaking coolinat out of my lower unit

thanks i was looking it up and it sounds like that or the impeller not sure yet

 

[stonyloam]

Re: leaking coolinat out of my lower unit

two most likely places, either you have coolant leaking into the seawater in the heat exchanger, or at the exhaust riser. A bad gasket 28 in this diagram http://www.mercruiserparts.com/Show...EXHAUST+MANIFOLD+AND+EXHAUST+ELBOW+(ALUMINUM) could allow coolant into the seawater at the riser. A coolant tube leak in the exchanger should show up in a sample of water taken from the seawater (aft) drain plug of the exchanger. Check out Mercruiser Manual #8 section 6 in the "adults only" section. A cooling system pressure test is probably a good idea (tools available free at Autozone). The impeller would not be the problem. Good luck

 

[snyman]

Re: leaking coolinat out of my lower unit

the link wont work for me. Thanks for the advice. What are the steps to find out if that is the problem. or what to do like i said im new to boat and dont know a dang thing about it. thanks

 

[snyman]

Re: leaking coolinat out of my lower unit

got it to come up thanks i will try that to. Post when i find out the problem. you guys are good on here and glad you know what your talking about save me a lot of money thanks again

 

[snyman]

Re: leaking coolinat out of my lower unit

just took off the heat exchange. Water runs freely out of the coolant and out of the seawater side. Any ideas on how to test for leaks in it or should i just take it to a radiator shop and have them look at it

 

[zbnutcase]

Re: leaking coolinat out of my lower unit

Take it to a GOOD radiator shop, they are equipped to pressure test 'em

 

[ken_23434]

Re: leaking coolinat out of my lower unit

Make sure you download the Mercruiser service manual for your engine and drive that is in the Adult's sticky at the top of the forum.

Almost all the manuals are available in that sticky and there is no charge for them.

 

[stonyloam]

Re: leaking coolinat out of my lower unit

just took off the heat exchange. Water runs freely out of the coolant and out of the seawater side. Any ideas on how to test for leaks in it or should i just take it to a radiator shop and have them look at it

Check the fresh water from the exchanger for the presence of antifreeze.

 

[ken_23434]

Re: leaking coolinat out of my lower unit

just took off the heat exchange. Water runs freely out of the coolant and out of the seawater side. Any ideas on how to test for leaks in it or should i just take it to a radiator shop and have them look at it

You can use the automotive type radiator pressure tester to pressurize the FW side of the system (you would need to hook up the hoses again to the cooler, but I would leave the sw hoses off). When you pressurize it, the pressure should stay steady. Based on what you said, I would guess you will see coolant come out one of the seawater ports on the cooler.

Autozone will "loan" you the pressure tester. They charge you a deposit for the tester, when you are done they refund you fully. It's one of the tools on their "loan a tool" program.

 

[snyman]

Re: leaking coolinat out of my lower unit

well after waiting for a week for the gasket. I finally got it and its the wrong one so i got to wait another week. The heat exhange turns out to be good so will post progress when i get the gasket if i ever get the right one

 

[snyman]

Re: leaking coolinat out of my lower unit

OK i got all the parts back together. The impeller was shot to crap. There was not a gasket on the manifold. Not overheating and now sucking water up the lower unit. Now when i give it gas it dies i belive that i might have messed up on the lower part of the unit and didnt get it back together right any anwsers will be helpfull thanks