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Not sure how to proceed. Blown head gasket, head or worse...

Philster

New member
My dilemma:

Took a nice pleasant run with the Scarab w/ Merc 502 (8.2L) and did a routine check of the engine bay as usual before getting to far from home. I opened the hatch and saw two things of concern:

1) Salt water deposits and some water at the starboard side exhaust manifold join where it meets the engine (the exhaust pieces are new, and not leaking. There is no water jacket here at this joint, so I assume its coming out a cylinder or two?)

2) Blow by, which was so bad that it sprayed a watery oil out the blow by hose all over my hatch cover and a ominous amount of oil (choco milk brown) seeping out of dipstick tube. Very ugly. Oozed down into bilge.

I don't know how to proceed. Do I have the marina dig in and replace the head gasket and check the head on the starboard side? Was the blow by most likely a result of the water in the compression chamber, which forced up the compression and pushed combustion by-products past the rings and into the crankcase, where it became blow by?

Or... do I have a trashed engine? When a head or head gasket blows, can it result in that much blow-by? I'd actually be happy if I had to deal w/ just a head and gasket... considering the engine could be toast from the water. Now, she idled like a kitten, ran up to 59 MPH and started easily. I could have leaned into her for more, but I was doing a basic shakedown run as I was alone and wanted to check all things out since I got a new prop. It's a 60-63 MPH package. I got 59 w/out much effort and was doing so with salt water intruding into my engine (or at least with a blow head gasket or cracked head that was sending something somewhere it didn't belong internally).

Really need experienced opinions.
 
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want to save that motor? Right now today, change the oil and filter. Right after you do then run the boat with muffs on the drive, fresh water from a garden hose understand.

You want every drop of salt water out. Run it about a half hour, change the oil and filter again. Run it another half hour. Change the oil and filter again.

It will take about 3 oil changes with fresh filter each time.

Ok now you have the saltwater out.

Now heres the deal the heads got to come off anyway, what you have to decide is to pull the motor and work on a pallet or crate. Or in the boat, me i would work on a pallet. See whats what, i got a feeling this is worse then a head gasket, i wish it is a head gasket for your sake but maybe not then the motor will have to come out anyway.

While out you may want to turn the motor and pull the pan, i would but thats me.

Reason to pull the pan you may ask, oil pump service, peek at the main bearings,, a general inspection of the lower end.

Now to the question why the head gasket went? For that answer i got to ask a few questions about history of the boat.

This the first time out this year for the boat ? If yes then winterization was done wrong maybe.

Motor overheated ? Maybe you don't even know it did.

Think hard what happened to make the head gasket go or the block to crack or head to crack, what was done to the boat . Maybe this is a new to you boat i don't know you didn't tell us.

Quick now today do the oil changes or the block will be toast by tonight if this happened yesterday.
 
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exhaust manifold join where it meets the engine (the exhaust pieces are new, and not leaking.

If they are not OEM parts I would suspect defective exhaust allowing water into the engine. GLM mans. have a history of porosity problems.
 
What was the oil level when you first noticed the problem? Or if you didn't check and haven't done anything yet, what is it now? If it's unusually high (as a result of water getting into the crankcase), that could be the cause of the excessive blowby, which wouldn't really be blowby, rather a result of the churn produced from the crank webs and piston rod caps splashing around in the oil/water mixture.
What I'm suggesting is that there's a leak from the water passages in the manifold... not a head or head gasket issue, based mainly on your report of it running pretty well.
Such a leak wouldn't be much of an issue with the engine running, all the water leaking into the exhaust passages would get entrained with the exhaust and carried overboard.
When the engine is stopped, the water left in the system would enter in the cylinders through which ever exhaust valve happens to be open. Then as the engine cools and the clearance between the pistons and cylider walls opens up, the water trickles down into the oil pan.
The salt crusties could be due to minor weepage at the newly made up manifold to head joint, doesn't take much salt water to start making stalactities.
My advice:
Do exactly what chiefallen said to get the saltwater out of the engine, the longer you wait the more damage it will do.
But, before starting the engine in its current condition, pull the spark plugs and crank the engine over to make sure there's no water in the cylinders. Otherwise you'll be buying a new starter.
Take off the manifolds, block off/plug the bottom water inlet port, fill the water jacket with water and check for water leaking into the exhaust ports. Check the risers and spacers and gaskets for evidence of leakage.
If there's no smoking gun after that, then I'd start looking at the head/head gasket and bigger problems.
 
he said the milkshake is blowing out his breather, all over the place. That ain't a manifold problem.

Guy read the op again. I miss chit all the time on the first post.

I little water will disappear / evaporate.

Did you smell the oil ? Does it smell like gas ?
 
I guess I am thinking in a different direction. Too much water in the block is causing the blowing out of the breather. I hope he posts the results.
 
You both have great ideas, but I once saw a leaking hose leak soo long that it rusted a hole in the timing cover, and the water leaked into the oil pan.
That motor made alot of blowby. The owner "just knew" it was a head/head gasket/cracked block problem.
Chief is right. salt water will destroy the inside of that motor in a hurry.
Guy is right too, running it with water in the cylinder could be just as bad.

Drain the oil, change oil filter, remove the spark plugs. Put new oil in, and filter on.
I would drain the block and manifold of salt water now.
Leave the spark plugs out and crank that engine with muffs on.
If you get alot of water coming from the spark plug holes, take note of witch ones.
You might get water running from a plug hole without cranking if you have good pressure at the muffs.
If no water, put plugs in and crank a few times before you put wires on plugs.
Remove the plugs and check for water in cylinders. (you would now have suction in cylinders with plugs in)
If still no water, put wires on plugs and fire her up quick.
and so on and so on.
You will at least be pushing good oil just by cranking.
Change oil and filter again.
Hopefully by now you saved the block and have a better idea what to look closer at.
 
None taken Chiefalen. I'm not that well versed on engine internals as you are; just tell me when I am a dumbass and I'll understand.
 
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