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Overheating manifold, a lot off smoke

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Hi I need a big help from you! I´m brasilian, and we bought a second handboat, a 2012 Malibu wakesetter. Than, sorry about my english...

I read a lot off discussions in various foruns and I have a big indecision about the engine parts, I heard about the origem off a problem isn´t the water pump (it´s damage too, and our lake is very depth and we don´t have algae, ther was no obstrution), but the changes in the cooling passage, with an addition of the CAT system. A lot off owners sad that it´s stranguled the system. The temperature was so high that the manifolds melted in part, we were terrified to a explosion!

What we need to prevent another occurancce? What´s really happened? we will go to California in the end of November and I´d like to bring the pieces on my own.

Thanks a Lot!

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I just had an issue with mine.  It is a 2004 with a 2012 engine in it.  There was a recall on the circulation pumps is 2012.  You need to pull that off and see if it has been replaced or if it is the original that was prone to failing.  

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Well I dont think so, because it was bought for a brasilian in first hand. But the question is, changing the pieces there are damage, we will be protected for the same problem ahead? And the coments about the decrease in water flow, in consequence off legal changing about the CAT in manifolds? 

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To answer you question, yes changing out the parts should take care to prevent further issues.  I am not sure on the CATS as my boat does not have CATS, maybe someone else will chime in on them.  

There are 2 water pumps on your engine.  Te Raw Water Pump pulls water in from the body of water and supply's the engine.  This is the pump that has the rubber impeller that need to be replaced every couple of years.  Then there is the Circulation Pump that circulated water through the engine to keep things at the proper temperature.  

Below is the circulation pump that I just replaced on my boat (2012 engine).  In the first picture is where the pulley will attach to the pump to hold the belt.  On the Back of the pump is a Stainless Steel plate that has a part number stamped into it.  

There was a Service Builtin regarding the bad pumps.  SB2013-1  This affects 5.7L engines with Serial Numbers 170158 to 172350.

Stamped into the plate, if the first 5 numbers are below 12027, then the pump must be replaced.  My first 5 numbers were, 11320.



Edited by blk93jeepzj
added additional info
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Looking at this photo of the engine you can see where the circulation pump is located.  It is held on by 4 bolts.  The bottom Right bolt also holds the alternator bracket too.


Here is what the inside of my pump looked like, impeller was cracked.  Causing my engine to overheat and go into Limp mode.  


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I think the OP has an overheating exhaust manifold, not an overheating engine block?  If so, he should look first at the impeller, hoses, and trans cooler.

OP, is it a Hammerhead 383?  If so, take a look at this thread:


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@Patricia:  Look for a bad impeller in the raw water pump (the one that should be mounted on the crankshaft pulley and will be below the water circulation pump), check the transmission cooler for debris (remove the hose leading to it), check the water circulation pump (previous post with pictures) and also replace the plastic hose fittings on the CATS, they probably are melted and if not, will fail soon (an item to buy when you are in USA).  CATS may need to be inspected for damage also.

You might want to take several pictures of the items and visit a Malibu dealer when in California to get more advice on repairing any damage.

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Thanks a lot. You´re right, the manifold was melted, we check the impeller and it´s not ok too. The engine didn´t stop or diminish the rpm, how it had to. We stopped the engine as soon as we note we note the smoke. I saw the place of the water circulation and tomorrow we´ll do the inspection about the other itens. The exhaust manifold has to be larger than the original?


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  • 1 month later...

May be worth a read of this post regarding a cooling system upgrade.

did this to my 2011 model and after a surf when the engine is under the most load, the CAT manifold is as hot as a cup of coffee.

thise Dapco tight return hoses took a bit to track down, the rest is just straight hose.

i can hold my hand on the manifold for about 10 seconds with no risk of burns.

the other area to check is should some parts of the raw water impeller come off they will lodge themselves in the transmission cooler restricting water flow.

just remove the hose from the raw water pump to the transmission cooler and look at the face of the cooler for any pieces of impeller rubber.

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