4.3 GL water in oil

[4.3 Sunbird]

1995 Sunbird with 4.3GL always been stored inside heated shop over winter, always started and ran excellent. Early this summer was doing a preseason flush, started engine, ran for about 30 seconds and noticed milky oil coming out of PCV hose at carb. Turned off immediately.
Any ideas on what could have happened since impossible it could have froze?
What are my next steps, I consider myself mechanically able to tackle this just not sure where to start.
Any info would be appreciated.

 

[jimmbo]

Was the Block and Intake Drained of ALL Water, during the Storage Period?
How Cold did it get outside during winter?
While it is Possible that the Head Gasket is leaking, or a Head Has a Crack in it, 99+% of the Time, Water gets into the Oil, cause the Block and/or Intake Froze
A Pressure Test of the Cooling Passages in the Block is required.

 

[4.3 Sunbird]

Thanks jimmbo.
First of all, the engine was winterized this past year and boat is always in heated shop at no less than 10 degrees C. I used to winterize it yearly since 1995 when new when it was stored in unheated storage unit but since 2012 it has been in my heated shop and has never froze.
What is the correct process for flushing the engine? I will do the pressure test but feel I should flush the water jackets first. Currently oil / water is drained.

 

[Scott Danforth]

just drain the water jackets, then pressure test. should hold 15psi forever.

if it doesnt, follow the sound of the hissing

 

[4.3 Sunbird]

just drain the water jackets, then pressure test. should hold 15psi forever.

if it doesnt, follow the sound of the hissing

Thanks for the advice

 

[ESGWheel]

You did not mention if you detected water in the oil pan (dipstick with dreaded milky foam) or if you changed out the oil and/or oil filter and found evidence of water. Where I am going with this is I wonder if it was condensation build up vs. water jacket leak. Also, something that is relatively easy to do is pull off both the valve covers > is there pervasive milky substance everywhere? > water in oil. Good luck and post how it goes and any questions.