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tminihan
Joined: 10 Jul 2008
Posts: 33
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 Posted: Mon Dec 07, 2009 9:59 pm Post subject: XK19 Milky Oil, Good Compression |
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| My 1971 XK19 has the 350FLV. While changing the oil for winterizing I noticed my oil was slightly milky. I performed a compression test: 135-165 psi. If I had a bad head gasket I would have expected much lower numbers on one or more cylinders. This is my first boat, so I'm not terribly familiar with raw water cooled engines. Other than an intake manifold gaskets, is there anything else that might cause this? Thanks, Tom |
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drrot
Joined: 14 Nov 2005
Posts: 729
Location: McHenry, IL 60050
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| Posted: Tue Dec 08, 2009 8:13 am Post subject: |
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Tom,
Could be any number of things. Mark the current oil level and run it some more. See if it increases. If it does there is a problem somewhere. If not it could be condensation.
My first step would be to isolate the cooling system and pressurize it with air. Listen for leaks. |
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jahearne
Joined: 03 Nov 2008
Posts: 279
Location: San Francisco
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| Posted: Tue Dec 08, 2009 1:03 pm Post subject: |
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Isolating the cooling system on a raw water engine could prove challenging. There's got to a be a special tool kit and/or proceedure. A water leak at the head gasket might not leak into the combustion chamber and wouldn't be picked up by a leak down or compression test. I can't think of where water could enter the oil except at a head or intake gasket or a cracked water jacket again on one of the heads or intake manifold. Water jackets at the cylinder walls could crack too. I wouldn't wish that on anybody. Hope for a bad gasket somewhere.
Good luck,
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John & Wendy |
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tminihan
Joined: 10 Jul 2008
Posts: 33
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| Posted: Wed Dec 09, 2009 8:32 pm Post subject: |
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| Thanks drrot and jahearne. I'll replace the intake gasket and cross my fingers! Tom |
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ed laning
Joined: 07 Nov 2005
Posts: 242
Location: spring lake, mi
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| Posted: Thu Dec 10, 2009 8:59 pm Post subject: |
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I don't know if you have on that engine any kind of oil cooler or not. If you do, I would pressure test it first. It's fairly straight forward.
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1978 22' CC Dory outboard |
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THE RAZZ
Joined: 20 Apr 2006
Posts: 572
Location: OAKLAND, CA
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| Posted: Fri Dec 11, 2009 9:28 am Post subject: |
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Tom,
Re-compression test: 135-165 psi.
That spread is near 20% and is suspect. The water in the oil should be unrelated. However, 20% is big.
Sometimes a leakdown test is possible. Rotate engine by hand. Bring 135 psi cylinder up on compression stroke.
Listen to that cylinder through carb/ then exhaust pipe/ then dipstick tube.
Loud carb-exhaust air leaking air sound could mean a valve job.
Loud air sound through dipstick could mean rings aren't sealing.
None of about could mean head gasket.
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1942 17' barrelback 71923
1987 21' CC Stinger |
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