I'm hoping some of you bored diesel mechanics who have seen a lot of engines can answer this one--a very minor water seepage from one of my water intake lines has left a round spot on the block where the engine paint is gone and instead is a layer of wet crystalline stuff that seems to be corrosion of the block itself. It's gone a little deeper than I expected and I have to wonder what salt water is doing from the inside of that casting if so little water has done that on the outside. Despite the frequent suggestions that we flush the intakes with freshwater I doubt many people really do that, and yet I'm not reading any complaints of block failures for these marine diesels. Should I be worried here? Do the intake castings on these blocks corrode through from salt water? are there places where zincs should be placed? A complicating factor is that my boat is showing signs of a possible electrical grounding problem ("magnetic" rust patterns on locker hinges, rapid loss of zincs) that may be from inside or outside the boat.
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I'm hoping some of you bored diesel mechanics who have seen a lot of engines can answer this one--a very minor water seepage from one of my water intake lines has left a round spot on the block where the engine paint is gone and instead is a layer of wet crystalline stuff that seems to be corrosion of the block itself. It's gone a little deeper than I expected and I have to wonder what salt water is doing from the inside of that casting if so little water has done that on the outside. Despite the frequent suggestions that we flush the intakes with freshwater I doubt many people really do that, and yet I'm not reading any complaints of block failures for these marine diesels. Should I be worried here? Do the intake castings on these blocks corrode through from salt water? are there places where zincs should be placed? A complicating factor is that my boat is showing signs of a possible electrical grounding problem ("magnetic" rust patterns on locker hinges, rapid loss of zincs) that may be from inside or outside the boat.
Any thoughts on the grounding plate?
Okay, nobody wanted to answer my original post, but now I've discovered something new and interesting so I'm throwing my question back to the top of the pile. It turns out that a rectangle on the bottom of my hull is a grounding plate/lightning diffuser that probably isn't supposed to be covered with bottom paint, but is, and may always have been. Nonetheless, I still really don't know how it's intended to work. Will it suffer electrolysis over time and need to be replaced? Is that what's supposed to happen? How often would it be replaced? Should one have zincs on the nearby prop shaft when one of these is present? Will it create a field in the water that will alleviate some of the electrolysis on the shaft zincs? And the biggest question, will it get covered with barnacles? Is there something that can be painted on to stop them? Somebody out there must know something...
Okay, nobody wanted to answer my original post, but now I've discovered something new and interesting so I'm throwing my question back to the top of the pile. It turns out that a rectangle on the bottom of my hull is a grounding plate/lightning diffuser that probably isn't supposed to be covered with bottom paint, but is, and may always have been. Nonetheless, I still really don't know how it's intended to work. Will it suffer electrolysis over time and need to be replaced? Is that what's supposed to happen? How often would it be replaced? Should one have zincs on the nearby prop shaft when one of these is present? Will it create a field in the water that will alleviate some of the electrolysis on the shaft zincs? And the biggest question, will it get covered with barnacles? Is there something that can be painted on to stop them? Somebody out there must know something...
As To Your First Question
No, don't worry about the block. First, tho, is your engine fresh or saltwater cooled? If fresh water, the corrosion will be in the heat exchanger. If it's salt-water cooled, you shouldn't have any air in the cooling system and there will be a zinc protecting the engine from electrolysis. As for the second part, your most certainly will remove the paint from the ground plate. However, I'd really have a trained marine electronics tech go over that boat to check for stray currents or bad grounding. I'm a LONG way from being anywhere near conversant to give you any more opinion than that. Others will do a better job, I'm sure. Rick D.
No, don't worry about the block. First, tho, is your engine fresh or saltwater cooled? If fresh water, the corrosion will be in the heat exchanger. If it's salt-water cooled, you shouldn't have any air in the cooling system and there will be a zinc protecting the engine from electrolysis. As for the second part, your most certainly will remove the paint from the ground plate. However, I'd really have a trained marine electronics tech go over that boat to check for stray currents or bad grounding. I'm a LONG way from being anywhere near conversant to give you any more opinion than that. Others will do a better job, I'm sure. Rick D.
crystalline stuff
Rich: The "crystalline stuff" is probably just salt build up. You can clean the passages of the block by flushing it with a product called Marsolve. I think the company has been purchased and is being marketed under a new name, but you should be able to find it on the internet under the old trade name. I would have to go with Rick on the corrosion. You may want to have the water checked for stray electrical. This can also be caused by your own boat too. You did not mention what engine we are discussing here.
Rich: The "crystalline stuff" is probably just salt build up. You can clean the passages of the block by flushing it with a product called Marsolve. I think the company has been purchased and is being marketed under a new name, but you should be able to find it on the internet under the old trade name. I would have to go with Rick on the corrosion. You may want to have the water checked for stray electrical. This can also be caused by your own boat too. You did not mention what engine we are discussing here.
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