7.4L just purchased boat , water in oil. How to identify issue ?

Ten Years Gone said:
Look, no one on this forum wants to bust your balls, but you are not approaching this in a methodical manner, and moreover, you are running the risk of doing more damage if you don't get rust preventive measures done immediately!

You have a V-8, so you need to pull ALL the plugs! And please explain what kind of compression test is done "under water", and looking for bubbles? A compression test is done with a simple tool. What are you doing exactly to come to a conclusion that "all looks good"? :huh:
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I think he's saying that he pressure tested the oil cooler for leaks using compressed air while placing the cooler under water and looked for bubbles...
 
Yes I was testing the oil cooler in a bucket of water and pressurized it under water with air. Just a quick way to see if there is a split in the cooler and it held the air.....no bubbles. going to flush oil this morning and see what happens with fresh oil.
 
Through this process of elimination doing a compression test will isolate the head should some readings comeback low that would point to head gasket or cracked head am I correct ?
 
You want to pressurize your cooling system, forget about the compression test. Your going to have to block off some hoses [ exhaust] and get a shraider valve in the mix somewhere, pump it up and listen for air from the valve covers.
 
Ten Years Gone said:
Look, no one on this forum wants to bust your balls, but you are not approaching this in a methodical manner, and moreover, you are running the risk of doing more damage if you don't get rust preventive measures done immediately!

You have a V-8, so you need to pull ALL the plugs! And please explain what kind of compression test is done "under water", and looking for bubbles? A compression test is done with a simple tool. What are you doing exactly to come to a conclusion that "all looks good"? :huh:
Click to expand...

Agreed,

If your only willing to pull 2 of 8 plugs and don't see the need to check engine compression..?

I'm out.

Good luck.
 
Lots of logical and good advice above....get the motor spun up and get all moisture out of it. That is your first priority! Then deal with the trouble shooting later. Each day gone by is a day where moisture and O2 are having a party in your engine.


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Did 2 flushes on crankcase. Oil is looking fairly clean but want to do one more from drain pan ... any trick to this and what/ where is the best way to get at the drain plug. Mark the reason I only got at 2 of the plugs is a physical issue as it is difficult for me to maneuver to get at all the plugs . My son is going to come by on the weekend to assist. Thx again for everyone's input
 
Lets see where oil and water can come together.
Oil cooler. You tested that.
Crack between oil passage and engine block. 1. head gasket but usually you see water on the cylinder with much white smoke from the exhaust (already mentioned). A compression test would rule this out to some degree. 2 Internal crack in the block caused by overheating or water passage frozen over the winter. 3 condensation from prolonged sitting which will dissipate after a couple oil changes and warm ups. The problem with this one is that you run the risk of further damage on point 1 or 2 if you continue to warm the engine trying to evaporate the water off.

Just my opinion. What else have I missed guys?

As far as using muffs I have been using them for a number of years on many different motors and have had no water intrusion due to them. Again just my experience other may no agree.
 
Update ran motor for a while ...oil all clear . Still will do compression test in the morning but nervous if that test comes back good .
 
Compression done and all read between 147 and 152 psi. Did a kill switch run on motor with muffs at full blast and then check plugs again to see if manifolds with leaking water into cylinders. No issues there as well. In the ocean she goes tomorrow and I will see what unfolds.
 
Sea trial did not go well. Motor was running warm and when I went to plane out the temps shot up and alarm came on. Let cool down and limped home......back to step one
 
flush out all the oil again. start removing the plugs and see which ones are wet. that would probably be the side with a bad riser or gasket.
 
jeffc said:
Sea trial did not go well. Motor was running warm and when I went to plane out the temps shot up and alarm came on. Let cool down and limped home......back to step one
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In your first post I noticed that the raw water pump was inoperative when you started the engine on the muffs, and you replaced the pump, but did you check to see if the impeller on the old pump was intact? If it disintegrated and pieces of the impeller were sent through the engines cooling ports, you may have some blockage some place that is causing your high temp readings. Just a thought when you start the trouble shooting phase again. Good Luck.
 
I had overheating issues when not on the muffs. This was due to the engine thermostat being stuck. The muffs would force enough water to keep it cool on the hard but when in the water there was no pressure to push it through the engine. Try using a large tub like a plastic tote bin. Fill it with water and lower the drive into it over the water pickup. See if it picks the water up out of the tote. (Make sure you keep the water running in the tote).

Is there water in the oil again?
 
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There has been much said about water intrusion from the manifolds. The only way water could get into the oil is between the cylinder wall and piston. There are no other areas that share the intake and exhaust. The head is sealed from the cylinder so no water there. The exhaust port is fed from the cylinder and even with the exhaust valve open the intake valve would be closed so no water in the intake manifold.

If water is making its way from the cylinder past the piston you would have no compression and many more issues than condensation in the oil. The engine would most likely never start and if it did you would have white smoke (water vapor) out the exhaust.

Just my opinion. Let me know if you think I am missing something.
 
Correct I had to change impeller and there not a fin left on it ... so chucks of it must have went through the cooling system. I found a chunk in the oil cooler . Question is where is the rest of the chunks and where best to look and remove them ?
 
Sorry forget to mention Risers were nice and cool when motor was running real hot
 
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