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iokua
11-14-2004, 09:58 PM
Now that I finally seemed to have the mechanical problems on my '85 S&S taken care of, I decided to double check a high oil level. Just before I purchased the boat, the owner changed the oil, so I figured he just over filled it. So I decided to drain some of the oil, since it was overfilled by quite a bit. Unfortunately, when the oil started draining, it's color changed from a nice brown to a milky brown - uh oh!

My first guess (and hopefully worst case) is blown head gasket. Now I'm wondering if it's just because the boat sat for 3 years, but he did just change the oil, so I doubt that much water would be left in it.

My plan was to drain the oil, refill with new oil, and run for a few minutes connected to a water source. Then shut it down and check the oil level/color.

My only concern is that if the head gasket is blown (or worse), I could risk doing further damage.

How can I check the engine out without running it?

Mag_Red
11-14-2004, 10:01 PM
You could do a compression check or take a sample of the coolant and go to the local radiator shop and request that they analyze the coolant for the presence of hydrocarbons. If they are present then it is most likely that you have a blown head gasket.

JimN
11-14-2004, 10:49 PM
Your leak could be from a lot of things. Bad intake manifold or head gasket, cracked head or block, etc. Unfortunately, there won't be a quick way to tell where the problem is. You do sound pretty mechanically inclined so if it requires disassembly, it shouldn't be an impossible task. I would start with the intake manifold and look at the gasket. If this is OK, pressure test the manifold. The heads would be next. They can be pressure tested and magnafluxed to check for cracks. If cracked, you'll need to replace, but they aren't too expensive. If you look at the motor and see any silicone gasket sealant at the intake manifold where it mates with the heads, see if the gasket was already replaced. Same for where the heads mate with the block. There shouldn't be gasket sealant at these joints. If there is, at high temperatures, the silicone gets soft and the expansion in the cylinder(s) can blow it out and cause leaks. If you get lucky, bad gaskets is the problem.

Also, look for replaced freeze plugs. If you have any new ones, it froze. Ultimately, the boat is more important than just the motor. A major problem with the hull/deck can be a lot more expensive to repair than the motor.

Since you had it running with the wrong firing order and it was either in water or connected to water for cooling, it's possible that water was sucked into the cylinders and when it got to the compression cycle, some was forced past the rings, into the crankcase.

iokua
11-15-2004, 10:49 AM
Thanks guys;

There are 2 freeze plugs that have been replaced. They look like non-professional jobs.....I did notice silicone sealant at the exhaust manifold too. Since the compression check turned out okay, I guess my next step would be to pull the exhaust manifold and put down a new gasket. I haven't checked the head gaskets, but I can do that when I pull the manifold.

I would hate to have to pull the engine apart to replace the 2 freeze plugs the right way, but I'd also hate to replace the exhaust manifold gasket and put it back together only to find out that it was actually the freeze plugs.........comments?

Diesel
11-15-2004, 11:48 AM
Thanks guys;

There are 2 freeze plugs that have been replaced. They look like non-professional jobs.....I did notice silicone sealant at the exhaust manifold too. Since the compression check turned out okay, I guess my next step would be to pull the exhaust manifold and put down a new gasket. I haven't checked the head gaskets, but I can do that when I pull the manifold.

I would hate to have to pull the engine apart to replace the 2 freeze plugs the right way, but I'd also hate to replace the exhaust manifold gasket and put it back together only to find out that it was actually the freeze plugs.........comments?

Hate to say it but usually the freeze plugs are replaced for one reason......... the boat was not winterized properly and they popped out when the frozen water expanded. You could be looking at a cracked block and or head.

Follow Jim's steps and you should be able to narrow it down. Good luck :)

JimN
11-15-2004, 11:59 AM
Don't worry about silicone at the exhaust manifolds. That's how they attach them. You may be able to replace the freeze plugs without pulling the motor. If you support it underneath and remove the motor mount that's in the way, you should be able to get in there.