I'm stumped, overheated 4.3 MPI, water in oil, replaced heads, still water in the oil

[chs marine service]

so i got this boat with a 2004 merc MPI, 4.3 engine. the customer overheated due to picking up a plastic bag and starving the impeller of water. i pulled the heads after finding low compresssion and had the checked for cracks and resurfacing. changedthe oil, etc... reassembled the engine and she ran great temp @ 150 for over 20 minutes,. i shut it down to finish cleanign the engine compartment and as i was about to sign off on a job well done, i checked the oil level and fouind i had over 2 gallons of wate/oil mix. i drained the system , flushed it out with diesel fuel, replaced the oil & filter.
started up, again, ran great but went into overheat, oil level stil ok,. i emptied the coolant system by means of the distribution bottle and started the engine to watch the flow of water getting to the engine. which was fine, i closed the valve and she ran @ operating temp again for over 20 minutes. thats as far as i went.
ive been racking my brain and i know i did not miss anything. the engine did not cook itself so bad that it melted the shutters and the bellows (exhaust elbow tubes) were fine so i have pretty much ruled out a cracked block but what else could i be looking for?

this is a dry joint manifold system and they were replaced when i had the heads off. when i had the heads off i did find that the water hose comign from the distribution manifold to the port side manifold was clogged with dirt/ silt for about 18" so i replaced that and checked the starboard side but it was clear. i stuck a pick into the engine block and did it was open.

 

[stresspoint]

if i had to guess , the intake has not sealed correctly , vortec intakes do that from time to time if toques are done incorrectly or too much RTV is used to seal pitting.
if heads were machined too much that can also create a issue of the intake angle going past limit.

as a marine mechanic , ?how did you determine the block is not cracked.

 

[chs marine service]

if i had to guess , the intake has not sealed correctly , vortec intakes do that from time to time if toques are done incorrectly or too much RTV is used to seal pitting.
if heads were machined too much that can also create a issue of the intake angle going past limit. .

hmm, well it has the plastic gaskets, new bolts and torqued properly. i spoke to the machine shop and they only tyook of 5 thousands of an inch,. not enough to through off the angle.
also ,if the intake was not sitting properly, i would think it would run rough or idle high, like a vacuum leak

 

[stresspoint]

hmm, well it has the plastic gaskets, new bolts and torqued properly. i spoke to the machine shop and they only tyook of 5 thousands of an inch,. not enough to through off the angle.
also ,if the intake was not sitting properly, i would think it would run rough or idle high, like a vacuum leak

probably felpro garbage ,
im , not a marine mechanic just a bloke that's worked on chev motors for years, iv added my opinion why you got a swamp in your customers motor ,so carry on , i hope you find the issue before you trash the crank running with all that water that's leaked in

 

[chs marine service]

probably felpro garbage ,
im , not a marine mechanic just a bloke that's worked on chev motors for years, iv added my opinion why you got a swamp in your customers motor ,so carry on , i hope you find the issue before you trash the crank running with all that water that's leaked in

im not looking to offend you, i took your info and called the machine shop, and im just thinking out loud. i guess my next move is to pull the intake and check for leaks otherwise, im looking at engine replacement.
this forum is to gather info, some good, some bad, some crazy, and sometimes those are the ones that solve the issue.

 

[chs marine service]

who do you suggest if not felpro?

 

[stresspoint]

who do you suggest if not felpro?

i only use OEM gaskets on any marine engines , especially vortec motors.

now , about the 5 thou off the heads , that should be OK , however , if the heads have had works done before then a another shop could have taken a good chunk off and it was not realized by your guy. hence why a measurement should be taken before heads go to the shop for work.
there is a service limit in the manual , if you look it up you can check once you remove the manifold.

another thing that rears up every now and then on vortec heads is rotted out exhaust runners , ? was this checked for before machine works were done.

? again , how was it determined that the block is not cracked or rotted out .

 

[Bt Doctur]

you mention the bolt torque, no more than 14 Ft/lbs

 

[Bt Doctur]

file:///C:/Users/Edeward%20J/Downloads/Intake%20torque.pdf

 

[chs marine service]

you think MERCRUISER makes their own gaskets?

the engine is virgin, never been opened up prior to this incident. 356 hours on a lake boat so it is highly improbable that the block is rotted.

other than visual inspection ,i did not do anything with confirming the block is ok. i did note that the rubber in the exhaust was not melted so i do not believe the engine got hot enough to crack the block.

intake was torqued in sequence, 33, 106, 133 inch lbs

 

[stresspoint]

you think MERCRUISER makes their own gaskets?

i spend the extra to ensure a reliable seal , the OEM Mercruiser gaskets are the best quality i have found for SB boat motors, so who makes them is irrelevant to me , i use them when working on Mecruiser motors because for me its worth the spend to do the job once and know its done right.

you buy what you like for your customers boat, its you time that it takes to replace them and fix any consequential damage when a cheapo AM gasket leaks.

try not to do too much more damage while you flounder around on boating forums trying to rectifie what you messed up.

I'm out !.

 

[chs marine service]

i spend the extra to ensure a reliable seal , the OEM Mercruiser gaskets are the best quality i have found for SB boat motors, so who makes them is irrelevant to me , i use them when working on Mecruiser motors because for me its worth the spend to do the job once and know its done right.

you buy what you like for your customers boat, its you time that it takes to replace them and fix any consequential damage when a cheapo AM gasket leaks.

try not to do too much more damage while you flounder around on boating forums trying to rectifie what you messed up.

I'm out !.

i don't know why your so hostil on these posts. do you think i want to be here? do you think i want a problem like this lingering? im trying to gather as much intel before i make my next move. for some reason from the 2nd post on, i feel you've been attacking me for asking opinions and kicking ideas back and forth.

 

[Scott Danforth]

Mercruiser uses the same gasket suppliers as GM and other OEMs

Check the block for a crack. Lifter valley, just under the deck

 

[Lou C]

Did the machine shop magnaflux the cyl heads or dye test them? How did they determine that they weren't cracked?
when I had my episode with water in the oil in my 1988 pre-Vortec 4.3 and in the 2 front cyls, what I found is that it was from the fire ring of the head gaskets on both sides splitting near a water passage. This would let water seep into the cyls after the engine cooled off. Not enough to hydrolock but enough to turn the oil milky. Had an overheat in 2013, the HGs started leaking at the end of the '16 season.
I pulled the heads and took them to a machine shop, they found that both had cracks in the center cyls exhaust seat areas. And after close to 20 years of salt water use the cooling passages were getting eroded. So I wound up replacing them with a set of reman heads. Ironically the cyls with water in them were the front tow cyls (#1 and #2) the center cyls with the cracked exhaust seat area didn't have water in them, so it all came from the HGs.
Inspected the block as best as I could didn't find anything looking like a crack so rolled the dice and put the heads on with Fel/Pro marine gaskets and ARP head bolts.
Since then (2017) I've done several oil analyses and had no water in the oil.
Not sure if the sealing of the Vortec intake is more problematic than the pre-Vortec, but I never heard of small block Chevrolets having leaking intakes till the Vortecs came out.

 

[stresspoint]

Mercruiser uses the same gasket suppliers as GM and other OEMs

Check the block for a crack. Lifter valley, just under the deck

the block cant be cracked , it didn't over heat long enough

 

[alldodge]

Reading 4.3 MPI head flatness is ok at .005 , not for me


FelPro Marine is the only ones I use, but hey that's just me

Intake Torque spec for intake is correct

There are 2 different methods to torque heads but if your following manual 32 then all good

When was last time Torque wrench was calibrated?

 

[nola mike]

Reading 4.3 MPI head flatness is ok at .005 , not for me

.005 was milled, don't think he was referring to the flatness