Crusader 454 Coolant in Oil

[pkrawetzky]

Last year (2011) I noticed I was using some coolant over the summer season. The coolant was being drawn from the overflow container after the engine was stopped. But I couldn't figure out where it was going. The engine oil looked fine and no noticeable traces of coolant. Winterized the engine for the winter including removing and filling the crankcase with brand new oil but did not run it after the oil change.

3 weeks ago I explained this to the marina mechanic and he suggested a pressure test. He performed the test using 15 lbs of pressure (my heat exchanged cap is 7lbs) and it didn't move. He conducted the test for 1 hour. He also pulled the plugs and didn't notice anything out of the ordinary, plugs had good color and no moisture (I had not changed the plugs yet from last year).

This past weekend I was ready to do the plugs, etc for spring commisioning, pulled out the dip stick and much to my surprise saw green coolant running down the dipstick.

I met the mechanic at the marina today and we did another pressue test. Pressurized to 15 lbs and it didn't move after 15 minutes. When he removed the test device you could hear the pressure escape so I know it was holding it. So back to square one.

I'm going to remove all the plugs and look in each cylinder to determine if there is any fluid in them. He also suggested turning the motor by hand (well wrench) a few times to see if that pumps fluid out of a cylinder. I'm also going to change the oil and refill it. He is also suggesting to fill it with coolant, run the engine to temp and redo the pressue test.

After some further discussion, he seems to think it may be an intake manifold gasket problem.

I'm just looking to get confirmation that this is the appopriate course of action. Has anyone else experienced this type of problem before? Thanks in advance for your input or suggestions. By the way the engine was rebuilt in 2004 with a remaned block (from Jasper engines), all other parts came off the old engine.

Pete

[Chief Engineer]

Have your mechanic put the gauge on and crank the engine. That may indicate a headgasket.

Some intake manifolds have a crossover in them for coolant.....leaky gasket.

Or you could have a failed oil cooler

[Nemo55]

Chief Engineer is right,,
I have seen some doozies in my time, if you can confirm the presence of coolant in the cylinders or in the crankcase(through dipstick even) that would be good enough for me to strip her down and do a new gasket set on her.
Why wait for engine damage to occur before you take action????

[pkrawetzky]

UPDATE

No coolant in the cylinders from what I can tell looking thourgh the plug holes. I know that is not much but it something.

Haven't done a compression test yet that is next. Also I removed one of the valve covers to look and see if there was any evidence of coolant at the top, nothing. I could see down inside the engine (all be it a limited view) and the rods, etc looks shiney, no rust. Again, I know that is not much but it's more information than I had.

@Chief Engineer - my oil cooler is also the transmission cooler and are raw water cooled, not fresh water. Transmission fluid is in perfect condition.

Also I'm going to pull the distributor and see if I can see something down inside there. Again I know it's not much but maybe I can get a better perspective. If this doesn't reveal anything, I guess I'll pull the intake maniforld and look inside there. I've never torn down an engine before but I'm guessing that has to come off anyway if I'm going to take the head gaskets.

[mtuva]

hi i have the same problem except i have coolant in the cylinders
did a compression check-ok
did a pressure check running-ok
what do you think? intake manifold?

[Chief Engineer]

PM me. Intake manifold gaskets may be the problem.

[mtuva]

it does not seam to burn any while i am running the engine but if the boat sits for a while it will leak into the cylinder
only does it on port side of engine

[pkrawetzky]

Update: it was the intake manifold gasket. The coolant was leaking near the right rear corner of the manifold. Refilled the system last weekend and the level stayed the same. Now we will see how things go after I run her a few times. Thank you everyone who replied.

[sdowney717]

Bad head gasket may show up as overheating or bubbles in coolant overflow tank.
A pressure test is only going to show leaks if they are really bad. So your leak must have only opened up when engine was hot and running. So consider a negative pressure test not definitive. Like on medical tests when you get erroneous results.