Another 470 with a coolant problem

tripbarb

Cadet
Joined
Jun 12, 2011
Messages
9
I was goin over my 83 four winns ski boat before i took it out last weekend and when i checked the coolant it was low. So i got the antifreeze and as i was pouring it in i noticed it was running out of the exhaust as fast as i could pour it in. And bfore anyone says it i know these engines are notrious for overheating. This thing has always ran great and cool to. I just need to know what would cause the coolant to run out of the exhaust as fast as i can pour it in? Thanks a lot
 

tripbarb

Cadet
Joined
Jun 12, 2011
Messages
9
Re: Another 470 with a coolant problem

Hey Thanks alot man, I just didnt know where to start looking as im kinda green to this particular engine. Like i was saying it just seemed strange that as soon as i started pouring the antifreeze in it started running out of the back of the boat i mean i was like well ok. So i checked to make sure it was coming from the bilge and it was actually running out of where the raw water comes back out on the out side of the boat on both sides and i was like well ok crap>
 

Desertsky

Seaman
Joined
Aug 25, 2010
Messages
73
Re: Another 470 with a coolant problem

Before you spend any serious money, make sure the gasket between the elbow and manifold isn't blown. That will also cause you to lose coolant and only costs a couple bucks to repair.
 

Desertsky

Seaman
Joined
Aug 25, 2010
Messages
73
Re: Another 470 with a coolant problem

Have you checked for water in the oil or on the spark plugs? This is an indication that the elbow may be rotted through. If everything is dry, it is likely that the leak is below the exhaust level. Remove the spark plugs and give the engine a short crank. No water should come out! If it does, then it is likely that the leak is above the valve level (exhaust manifold, etc).

On my 470, the raw water comes in and goes through a heat exchanger under the exhaust manifold (big round tube with hoses) and then exits through the exhaust manifold. I suspect that yours is the same since you have to add antifreeze. Another thing to check is the heat exchanger. There are gaskets on each end that can deteriorate and leak between the raw water and coolant. Again, the cheaper thing to look at first. Also, the heat exchanger can rot through internally. You can check this by removing al the hoses and filling up the coolant portion and look for water coming out the raw water tubes. Be sure to drain the exchanger before doing this and make sure the drains are closed! Used exchangers are $100 or so off eBay.
 
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