WATER in OIL!!! Mercruiser 120(1979)

[philtheskipper]

I have a little water in my oil. The oil on top of the lifters is milky brown and I'm getting that white build up on the filler cap and in the pvc tube. The oil level doesn't rise when I run the engine. Is this normal or do I have a big problem? Gasket bad? Block cracked? Any info would be greatly appreciated. Phil

[Fouled Plug]

Time to break out the compression tester! Sounds like a head gasket could have failed. Try the test and see how many pounds of compression you have, and how fast it leaks down. The good news is that head gaskets are relatively cheap and easy to install. Good luck!------------------I'm going to invent a TCW3/citronella oil blend and make a fortune!

[TONY H]

The compression test will tell the story.Depending on how damp your bilge is OR how much temputure deviation ther eis from the air above deck and below makes a diffrence.If you get a lot of condensation on the valve covers, that will cause that milkyness inside the valve cove, ie lifters, PVC. What doe the dipstick look like. Do you have this milkyness in the oil pan?

[philtheskipper]

The dipstick looks like good clean oil. I'm going to pull the boat out of the water this weekend and drain the oil to see what it looks like. I'll see if I can get a compression guage on it too. What should the compression read? Thanks for the help!

[philtheskipper]

Anybody know what the compression should be?

[hondon]

120 or better would be a good round about number but you are really concerned about how close those numbers are in comparison.

[philtheskipper]

thanks for the info!

[theMack]

Having same problem here! Is the Mercruiser 120 (1969) prone to blown headgaskets? Started engine and water/oil poured out of the oil filler cap. Spark plugs are clean but water in the pan as well as the top of engine. My understanding it's a Chevy Nova engine? Are engine parts interchangible? New to this.

[philtheskipper]

I'm no expert, but water and oil pouring out of your filler cap sounds like a much more serious problem than a blown head gasket. You (theMack) should post your question separate from mine and I'm sure you'll get a lot more help from others. My problem just turned out to be condensation . I don't think that a 1969 Chevy Nova came with a 120hp 4cyl. engine. It is probally a GM block though. Good luck, sorry I couldn't help!

[SNOOSE]

In Australia the 120 mecs are a Chev Nova but have had some mods done so you can't just use auto parts like water pumps and head gaskets but the internals can be substatuted with 307 parts. Now The Mack a blown head gasket will give you water in the oil and if the engine hasent had any serious work done to it fair chance it may be time that it is due to be rebiult and dont forget to get the manafold and exhaust riser acid dipped to cear out any rust in the water gallerys good luck I will have a beer for you.

[dsimpson]

Everyone loves to reply "head gasket" but you should know thay 99 times out of a hundred water in oil is caused by BAD exhaust.You should check risers and manifolds if your "condensation" doesn't go away. I just fixed the same problem myself and not 1 out of 250 people I asked told me to check my exhaust.Check for water in your dry exhaust ports!!!!!!!!!!