Next troubleshooting step?

[Lwapo]

I have had my boat out several times this year with no issues. 4-5 trips @ 4-5 hours each. Mostly trolling for fishing.

My motor is a 351W, I think it was originally marinized by PCM, but I'm not 100% sure. However, with my question, I dont' think the brand will matter....

I got home after our last trip and was changing the oil... milky oil

Insert swear word here...

Started looking into what the issue could be and had reason to suspect the intake manifold gasket.

Replaced the gasket including putting RTV sealant around each coolant port and the ends of each side of the intake manifold. Hand tightened, waited 1 hour, turned 1 turn, waited 24 hours, then torqued to spec (25lbs) in a rotating fashion from inside out.

I then made a homemade attempt to pressure test the cooling system. I went to the hardware store and bought a bunch of fittings and reducers to get from the water intake hose that goes to the outdrive into an air tool fitting. I took the two hoses that go to the exhaust manifolds and used a fitting to connect them to each other. Then, I pressurized the system to 20 psi. I heard no leaks and it held the pressure. I left it overnight and came back the next morning to about 14 psi. (I'm guessing either my homemade fitting or my cheap air compressor leaked, or the hoses stretched a little bit). In any case, I feel that it held pressure enough to say that the cooling system is secure.

I then changed my oil and filter. Ran my motor up to tempature for about 5 minutes, then shut it off.

Changed oil/filter again, ran it at tempature for about a half hour to 45 mins.

Oil is still milky? Has almost a white look to it.

What do I do next? I felt like if the water system was air tight, that it should not be able to leak?

I'm lost on what to do next!

Thank you in advance for any help!

 

[Bondo]

I have had my boat out several times this year with no issues. 4-5 trips @ 4-5 hours each. Mostly trolling for fishing.

My motor is a 351W, I think it was originally marinized by PCM, but I'm not 100% sure. However, with my question, I dont' think the brand will matter....

I got home after our last trip and was changing the oil... milky oil

Insert swear word here...

Started looking into what the issue could be and had reason to suspect the intake manifold gasket.

Replaced the gasket including putting RTV sealant around each coolant port and the ends of each side of the intake manifold. Hand tightened, waited 1 hour, turned 1 turn, waited 24 hours, then torqued to spec (25lbs) in a rotating fashion from inside out.

I then made a homemade attempt to pressure test the cooling system. I went to the hardware store and bought a bunch of fittings and reducers to get from the water intake hose that goes to the outdrive into an air tool fitting. I took the two hoses that go to the exhaust manifolds and used a fitting to connect them to each other. Then, I pressurized the system to 20 psi. I heard no leaks and it held the pressure. I left it overnight and came back the next morning to about 14 psi. (I'm guessing either my homemade fitting or my cheap air compressor leaked, or the hoses stretched a little bit). In any case, I feel that it held pressure enough to say that the cooling system is secure.

I then changed my oil and filter. Ran my motor up to tempature for about 5 minutes, then shut it off.

Changed oil/filter again, ran it at tempature for about a half hour to 45 mins.

Oil is still milky? Has almost a white look to it.

What do I do next? I felt like if the water system was air tight, that it should not be able to leak?

I'm lost on what to do next!

Thank you in advance for any help!

Ayuh,..... Is the oil level Risin' as ya run the motor,..??

Was that 45 minutes, pushin' the boat, or on the muffs,..??

At this point, the oil Level, rather than it's Color is important,...

 

[Lwapo]

I drained the oil last night and left the plug out to drain as much as possible. Then I refilled with fresh oil/filter this morning.

I also went to the auto parts store today and picked up a higher temp thermostat and (temporarily) installed it. My thinking was that if the motor ran a little bit warmer, it might help in getting rid of some of the moisture that could be remaining in the crankcase/etc. I ran the motor today in the driveway for about an hour while checking everything obsessively with a laser thermometer to make sure nothing got too hot.

While doing this, there was a steady, noticeable amount of steam coming from the valve cover vent. (I removed it to watch for that exact thing).

It does look like the oil level went up.

I now understand that it appears as if I still have a leak.

I was thinking that maybe there was a crack somewhere that only opened up when the engine was warm, so after running it for the hour, I quickly did another pressure test. It still held 20 psi for the 3-5 minutes that I watched it for.

The issue that I'm having, is how does the cooling system pressurize but then leak? It makes no sense to me?

Anything you can point me towards checking would be greatly appreciated. At this point, I don't know what to logically look at next!

Thanks!


"Running" the motor is by putting the outdrive into a very very larger Rubbermaid container and running it in the driveway at a hair above idle.

 

[alldodge]

I drained the oil last night and left the plug out to drain as much as possible. Then I refilled with fresh oil/filter this morning.

I also went to the auto parts store today and picked up a higher temp thermostat and (temporarily) installed it. My thinking was that if the motor ran a little bit warmer, it might help in getting rid of some of the moisture that could be remaining in the crankcase/etc. I ran the motor today in the driveway for about an hour while checking everything obsessively with a laser thermometer to make sure nothing got too hot.

While doing this, there was a steady, noticeable amount of steam coming from the valve cover vent. (I removed it to watch for that exact thing).

It does look like the oil level went up.

I now understand that it appears as if I still have a leak.

I was thinking that maybe there was a crack somewhere that only opened up when the engine was warm, so after running it for the hour, I quickly did another pressure test. It still held 20 psi for the 3-5 minutes that I watched it for.

The issue that I'm having, is how does the cooling system pressurize but then leak? It makes no sense to me?

Anything you can point me towards checking would be greatly appreciated. At this point, I don't know what to logically look at next!

Thanks!


"Running" the motor is by putting the outdrive into a very very larger Rubbermaid container and running it in the driveway at a hair above idle.

Your first post stated you joined the hoses together going to the manifolds for the pressure test. Since it still holds pressure my first thought is your manifolds are leaking water into the exhaust side. Water could be getting in and leaking down the cylinders while running. In either case my suggestion would be to pressure test the exhaust.

 

[Lwapo]

Agreed. I was actually thinking that before I rechecked this post. I will do so tomorrow and update again!

 

[Lwapo]

No Title

Ok, update time....

So I pulled off the exhaust manifolds. Given that the rest of the entire system will hold pressure, I'm convinced that there must be a problem with them.

I have the elbow style? I attached a picture of the style manifold that I have.

I removed the top part (riser?) and plugged the water holes on the bottom. Then I filled it with acetone and looked for a drop in level and/or a leak.

Nothing.

I can't figure out how to test the top part? Any suggestions?

Thanks!

 

[Lwapo]

No Title

Ok, update time....

So I pulled off the exhaust manifolds. Given that the rest of the entire system will hold pressure, I'm convinced that there must be a problem with them.

I have the elbow style? I attached a picture of the style manifold that I have.

I removed the top part (riser?) and plugged the water holes on the bottom. Then I filled it with acetone and looked for a drop in level and/or a leak.

Nothing.

I can't figure out how to test the top part? Any suggestions?

Thanks!

 

[Lwapo]

No Title

Ok, latest update...

I was not able to figure out how to test the elbow part of the exhaust manifold and the 2 marinas near me both said that they could not either.

So...

I picked up a set of "log" style manifolds that were easy to pressure test and put them on. (I attached a picture that looks like them below).

I ran the motor for about a half hour to 45 minutes. The oil is still cloudy/milky and has increased in level.

I am at my wits end.

I can now same with a fairly high degree of certainty that I have pressure tested this darn thing from start to finish... what could it be?

I'm very frustrated and I'm going to have to start cancelling trips that are planned with family soon.

Can anyone point me towards something to try?

Thank you!

 

[Lyle29464]

Some times the plugs will tell you if they have had a water bath. I have have had some luck doing the following . Change out the front and back manifold bolts with a bolt that is about 4 inches longer. Start your engine as normal on a hose or in the water and let it warm up. After it has reached 160 or so shut it off and quickly remove the other bolts. Air tools are nice. slide manifold out to the end of the long bolts and look for water trying to run back into engine.