Cracked 5.7 engine

Mini hog

Mini hog

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Oct 19, 2013
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When running the engine on land I noticed some water dripping under the engine. I located the leak to a crack in the engine block.
Engine runs just a fine as it always have, motor oil looks fine without traces of water.

Is this repairable or is the only solution to replace the engine?


tempImageQIn2ax.jpg
 
nola mike

nola mike

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Unrepairable, your manifolds are probably cracked as well. How did you winterize it?
 
flashback

flashback

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I patched up a manifold with JB weld and it's still going 15 years later, but it has no moving parts creating power.

You need a new engine.
 
Scott06

Scott06

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Real repair is to replace the engine. But If you are lucky enough that it doesn't get into your oil after a couple of good hard uses , JB weld the crack and it is what is ...

There is something called lock and stitch to repair cracks but would think it wouldn't be worth it in this application.

My neighbors boat same issue took 3-4 uses before he started getting water in oil.

As mentioned check your manifolds likely the same issue. I would look at your winterization process because this is from improper winterization.
 
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flashback

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There's 2 significant cracks I see but there are more that these old eyes can't see. Ice damage is brutal to cast iron..
 
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flashback

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You might be able to get a short block and use the parts from your engine to finish it off. But be damn sure the parts are good..
 
Bondo

Bondo

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Scott06 said:
Real repair is to replace the engine. But If you are lucky enough that it doesn't get into your oil after a couple of good hard uses , JB weld the crack and it is what is ...

There is something called lock and stitch to repair cracks but would think it wouldn't be worth it in this application.

My neighbors boat same issue took 3-4 uses before he started getting water in oil.

As mentioned check your manifolds likely the same issue. I would look at your winterization process because this is from improper winterization.
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Ayuh,.... Ditto this,..... Lightly grind the area to expose the clean metal, 'n slather it with yer choice of epoxy,....

Then run 'er til she pukes,....
 
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flashback

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Bondo said:
Ayuh,.... Ditto this,..... Lightly grind the area to expose the clean metal, 'n slather it with yer choice of epoxy,....

Then run 'er til she pukes,....
Click to expand...
It's all relative, kinda depends on how old you are and how long it needs to run..
 
Bt Doctur

Bt Doctur

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did you probe the holes to remove the scale and rust clogging the drains?
without draining and just pouring AF in the hoses is useless
 
ScottinAZ

ScottinAZ

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in the automotive world, that is a fatal flaw. Automotive V-8's also run a pressurized cooling system much hotter than the marine versions run. The marine engine runs cooler, and also has an open cooling system, so your leak is just a leak. What you have there is freeze damage, and is going to attack the weakest place in the block, be it on the outside of the cooling jackets, like yours currently is, or the cylinder walls which will leak to the inside of the block, which you do not describe (clean oil). You may or may not have smaller cracks in the cylinder walls that have not manifested themselves by allowing water into the insides of the engine (where it does not belong, and will cause more damage). If this were my boat, I would probably epoxy up the cracks, its just an external leak at the moment, and start looking real hard for at least a comparable short block to replace it with. If in the interim there are any signs of water inside the engine, boat gets parked. Cracks get worse, boat gets parked..... you see where I am going with this????
 
L

LightningBob

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A 5.7 from a truck should be easy to come by and relatively cheap.
If it was me (and it was me at one point) I’d be shopping for a replacement right now and go through it in the garage; but I’d be putting a patch of JB on that and running it until it won’t go any more.
If you have the shop equipment and tools laying around and a full day to dedicate to it, I’ve had one out and back in the same day.

Depends on your budget
 
T

tank1949

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Mini hog said:
When running the engine on land I noticed some water dripping under the engine. I located the leak to a crack in the engine block.
Engine runs just a fine as it always have, motor oil looks fine without traces of water.

Is this repairable or is the only solution to replace the engine?


View attachment 362953
Click to expand...
It looks like 2 cracks. U would most likely have to pull engine to repair, so why not just replace it at that point. I have had some success at welding old Chevy v8 blocks that didn't have a pressurized cooling system, and I could access them easily in boat.
 
76SeaRay

76SeaRay

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Repeated heat and cool cycles from continuing to run the engine will invite the cracks to open further. When you normally go boating, how far are you from shore and how far are you from a tow if she dies on you while out on the water? That might tell you whether you want a temporary repair or not. Depending upon what year, truck blocks are fairly easy to find at a reasonable price.

Additionally, that crack is very close to the head. If there is a water jacket just above it in the head, you run the risk of a crack in the head as well if the water didn't completely drain from it.
 
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