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Rebuilding 1986 454 Crusader

"You mmay want to try it aga

"You mmay want to try it again with a bit mmore pressure. The oil side will see much mmore than "a few pounds" during operation. It also will warm and expand. Feedback received indicates when they open, the gap isn't large so the leak rate isn't fast either.

Also, consider that the water influx usually occurs when the oil pressure subsides and the engine cools, this activity draws the cooling water into the oil side. In other words, you may want to draw a vacuum on the oil side and see if the cooler holds it."
 
"Mark,

If I were you, I wou

"Mark,

If I were you, I would just get a new u-cooler. It sounds like you have a better than 50% chance it'll solve the problem. If not, you're going to want a new one if you rebuild the engine.

Something to think about since you have the old one out already.

Bob"
 
"Yes, I will get a new cooler.

"Yes, I will get a new cooler. But the fact is that it passed the leak test and is not the cause of the problem. As a preventetive measure I will put a new one back.
I still have to remove the intake manifold to see if the problem is in that gasket."
 
"Intake manifold water seal fa

"Intake manifold water seal failure, head gasket failure, block freeze damage, manifold water passage crack. Hopefully, just a seal problem and not an iron problem.
A coolant pressure test failure will indict the above, and clear the oil cooler."
 
No it is not freeze damage. I

No it is not freeze damage. I keep have kept things heated in there for about 5 years now and I have always kept thermometers in there that will verify it has never been frozen.
The head gasket is more or less ruled out since the spark plugs don't show any water on them. Never had excessive steam and engine runs very smooth and starts easily.
I am going to take the intake manifold off today and hopefully I will find the culprit.
 
""The head gasket is more

""The head gasket is more or less ruled out since the spark plugs don't show any water on them."

If my memory serves me, I believe there are adjacent oil/coolant holes in the head. I would not assume leaks make it to the combustion chamber and affect the plugs. I would do a coolant pressure test now, before the intake comes off. What happens if you remove the intake, and nothing is obvious there?

ps; many of the head bolts end up in coolant passages. Add that to my list as a possible leak point."
 
"Allright,

How can I do thi

"Allright,

How can I do this coolant pressure test myself.
I have not done that before.
What do I need for that?"
 
"Basically, an automotive radi

"Basically, an automotive radiator/cooling system tester. I use a snap-on little pump and integral guage. I have mine pump into the coolant overflow hose, so it tests the cap as well. Fill the system with water first, an pump to about 5 psi or wheneven the cap release point is."
 
Dave is correct on the head ga

Dave is correct on the head gaskets.

Most of the BIG auto parts stores will loan or rent you a cooling system pressure tester.
 
""if you go in on the flui

""if you go in on the fluid overflow hose your on the wrong side of the cap"

yes, but it works. With a recovery cap, there is a little valve that lets in air/water with little pressure differential. You can easily charge the entire system with air/water thru the overflow hose fitting. And, you can check the existing cap as part of the system, and, you can't over pressure the system. I like it."
 
"try daddyosmarine.com gen IV

"try daddyosmarine.com gen IV 350hp bobtails left and right shipped to n.j. from Fla. 12,800.fwc heat exchanger charging system raw water pocket pump everything! complete gauge,and custom wire harness with key switchs around 13,900"
 
"If I do a coolant pressure te

"If I do a coolant pressure test it will only show that I have a leak, right.
It will not show where the leak is happening. So it does not seem to make sense for me to do that. I know I have a leak.
The engine runs smooth and starts right up.
I have taken the oil cooler off and tested it and it did not show it was leaking.
I checked the spark plugs for signs of water in the cylinders and showed none.
This makes me think the intake manifold gasket is a likely suspect.
I thought of going ahead and take it off to see for signs of gasket failure.
If I can't see any on that, the problem will be the head gasket.
In that case I will pull the engine out and tackle that at a more convenient location."
 
"You know you have a water-bas

"You know you have a water-based fluid making its way into the oil pan. Is it coolant (fresh water based) or raw water ???

Regarding the pressure test, it will show where the leak is if in a visible area.

The coolant odor is pretty noticable, even in small concentrations. Lack of it usually points to a raw water influx. Last timme i checked, there aren't but two paths for this to happen and I think you've eliminated one."
 
One small question: Did you ru

One small question: Did you run the boat on plane AFTER you changed the oil and then saw water again? Or did you run the motor in the slip ONLY? Important!

Jeff
 
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