Milky oil, Headgasket?

[PARADOX]

I got some milky oil. I thought it as one of the headers.
Could be a head gasket ?
How can one tell if the head gasket is leaking? Where else could water get into the oil?

I feel dumb.. but what the hell.. I got to figure this out.

[insanity]

Take the spark plugs out and pressurize the water system with a garden hose clamped into your water intake hose. Plug the hoses to the exhaust manifolds/risers so you take the risers out of the equation, at least for the first test. If its a head gasket between a water passage and a cylinder, you'll get water coming out of one of the cylinders. Just watch your water pressure gauge and cut the hose off once you get about 20-30 lbs. If you have a leak in the block somewhere, you'll hear the water burbling and gurgling. If you don't find it that way and it holds pressure, then it probably is in the exhaust somewhere.

[MOBILEMERCMAN]

It can get in through exhaust. Head gasket, intake gaskets.

[Chris]

Intake gaskets are a much more common culprit. When a head gasket goes, you're usually losing cylinder pressure. The only oil passing thri the head gasket is through the returns. Not a likely place to have a failure- they're at very little pressure

[PARADOX]

Two cylinders have no pressure.
The rest are ok. I was hoping it's the header, but I just tested it. No leaks into the ports. So it's got to be somethng else. Headers would be the easiest to fix, but I'm sure I have to change head or intake gaskets and two cylinders. If I can do it, I play with it but if I have to pay to get it done.?.... it's not worth it. I was hoping for a "sticky valve" for lack of pressure.. and a leaky header. It's more.

[insanity]

Did you do a compression test to find the leaky cylinders? Which cylinders were they?

[PARADOX]

Don't know the numbers top of my head. Two inner cylinders on the right, looking at the front of the motors. Cyl close to me on right (no 1?) good. next, bad, next bad. last Forth on the right. OK. (I look at the numbers in the AM they on the block (350 V-8)
Did a compression test.

[Ratickle]

Here you go...

[Ratickle]

Anyway, first thought could be head gasket. Hope you're that lucky.....

[insanity]

Sounds like its time for brain (head) surgery Take pics, be interested to see what you find when the head comes off.

[PARADOX]

THanks.. OK then.. No 3 and 5 are shot. no comp.
I have no idea how to do a head gasket replacement. I will just start unbolting anything thats not welded.
Any quick short version lessons?

[Chris]

WAIT!! Before you start unbolting, get a leakdown tester and check each cylinder's condition. Once disassembled, this opportunity is lost. Why do the heads to find out you have a broken ring or something else wrong. The leakdown will tell you what shape the other cylinders are in and will help you determine what's wrong with your bad one's. If it's a valve, you'll have air noise in the carb or exhaust. If it's a ring, you'll hear it from the breather. If it's a head gasket, you may hear it in the breather or in a water jacket.

Having said that, you most likely have a gasket failure between the cylinders. That's most likely going to necessitate a complete disassembly and surfacing of the block's decks.

[PARADOX]

No worries.. No work in the dark. But that's sounds waaaaay more stuff I want to do.
I can go buy a leak down tester. But resurfacing? pheewww.. I hope not.
What I'm really worry about is setting the valve lash back to specs. I can handle pretty much anything taking it apart. Getting it back together, I always have left over parts but somehow I do manage to get things running.
I always wonder why some parts needed when whatever I work on runs with out them.

[old377guy]

same problem last season; pinhole in head combustion chamber. good luck

[Geronimo36]

What ever it is you want to get on it quick before the rust sets in... Come up with a game plan and knock it out expedentially so you can get it running again and burn off any remaining moisture... If you leave water in the cyliner long enough your rings will freeze up and/or pit the cylinders..

I don't mean to scare you but now is you're chance to catch this before it costs you any more.

[PARADOX]

THanks Ger... I always check the oil every time I take the boat out. I noticed it was milky soon. changed oil, flushed it.. changed it again. removed valve covers.. flushed,, added oil again.. started the motor for a few seconds. added oil.. so I think I cought it in time.. went through 3 gal of oil,, but I think the inside should be ok. (I hope)..

[insanity]

Is this motor in your Avanti or another boat?

[Geronimo36]

THanks Ger... I always check the oil every time I take the boat out. I noticed it was milky soon. changed oil, flushed it.. changed it again. removed valve covers.. flushed,, added oil again.. started the motor for a few seconds. added oil.. so I think I cought it in time.. went through 3 gal of oil,, but I think the inside should be ok. (I hope)..

When you found those two cylinders dead was there any water on the plugs?

Hopefully it's a head gasket and the combustion pressure is forcing the water into the lifter valley instead of the cylinder.

I'm curious what it turns out to be.

[PARADOX]

Is this motor in your Avanti or another boat?

The Avanti is great, no problems. These are in my Ole' Formula. The motors are early 90's Merc. 350 mag.

Ger.... It seemd hat there was some water in the cylinders and in the exhaust ports.

[Geronimo36]

Ger.... It seemd hat there was some water in the cylinders and in the exhaust ports.

I'd get the cylinders filled up with CRC or some tranny fluid before the rings seize.

Ahh, it's a small-block..... I'm gonna guess rotted head gasket or fatigued head.