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  1. #1

    Default "Hi, I have a 97 5.7 PCM SLL

    "Hi, I have a 97 5.7 PCM SLL high torque 350 in a Shamrock. The engine has 1400 hrs. and has been in salt water since new. The problem I am having is that there is water in the oil.
    I originally thought it was the intake manifold gaskets leaking so I removed and installed new. Iím still getting water in oil. I removed the oil cooler and pressure tested it, it was fine.
    I did a compression test and all was fine. With plugs out a visual inspection indicated one plug had small amount of rust or orange stain. Iíve seen plugs when salt water gets on them and this is no ware near the same. An automotive machinist told me to check under the intake manifold for cracks in the block, it all looked good. Is it possible that the engine being salt water cooled (even though it was flushed every time it was used) that internally it is rusted through? Will the heads rust through before the block? Is there any way to pressure test the block and the heads at the same time? Oh incase you are wondering I changed the oil and filter @ least 4 times before using the boat, only to find after a couple of hrs. used more water in oil. Great site, hope you guys can help, thanks."

  2. #2
    Join Date
    Jun 2008
    Windsor, Ca,

    Default "Dave, I've been thru this

    "Dave, I've been thru this to and it was a cracked block inside the valley, I did not see it un'tell the ran a test on it, also have them test the heads also!
    Was the motor ever frozen? from the cold."

  3. #3

    Default "Thanks Larry, No the boat is

    "Thanks Larry, No the boat is in Florida. How did you find the crack? The machine shop told me about the possible crack in the valley but i did not see anything. Have you ever pressure tested the entire cooling system? Thanks again Dave"

  4. #4
    Join Date
    Jan 2015
    Princeton NJ

    Default Re: Water in oil again

    I've been through this too with my 1998 PCM 5.7L. It was a rusted head bolt and we caught it in time. Rebuilt the heads (the block was tested and fine) fully. Change the oil and remove the heads - send those out to be rebuilt.

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