Another water in oil thread

[wil7483]

Hi everyone. I am sure that this has been tackled here a hundred times or so but I couldn't find an answer after searching the archives.

I re-powered my boat this spring with a Mercruiser 305 SBC engine. At the time I ran the engine for about 3 hours total out the boat with water supplied and found no problems. The oil was clean and the engine remained cool. I changed the oil and filter prior to placing the engine in the boat. The guy I purchased the engine from said that the manifolds and risers had been changed about a year prior to me buying it. The engine had a poor paint job so I removed the manifolds and other things and gave the engine a fresh paint job with two coats of high temp black paint. I purchased some exhaust manifold gaskets from an auto supply chain and put the manifolds back on. During the summer after placing the boat in the boat and running it on muffs I noticed steam coming from the dipstick tube and signs of water at the very top of the tube and not actually in the oil. I was assured that it was probably condensation and not to worry about it. The boat saw a total of maybe 1.5 hours of use this year in salt water due to not having a reliable vehicle to pull it. So it has mainly been run on muffs while I continue to work on it in the yard. When I went to winterize it last week I found the oil in the pan to be totally milky. I am wondering where the water is coming from? It has been a gradual migration to the state that it is in now so I am seriously doubtful it could be crack in the block. Does anyone think it might be the manifolds have failed? Or is it possible that the manifold gasket was not installed correctly or the wrong kind and that has caused the water to enter the engine.

Want to get a few suggestions before I spend the winter having this thing tore down. Thanks in advance guys.

 

[ziggy]

Re: Another water in oil thread

The guy I purchased the engine from said that the manifolds and risers had been changed about a year prior to me buying it.

if i was selling an engine, i might say that too.....

my manifold failed on my L6. it kinda happened slow. over two or four runs maybe. milky oil. i tested my manifold for a leak by fillin up the waterjacket with the manifold off the boat. it leaked into the exhust runner a lot...it was my problem.
ya could pressure test yer block for leaks with it all together.

ya might assume it's a gasket since ya used a auto gasket. use only marine gaskets. for me, oem if i can get them......

some folks might be interested to know the year of yer 305 sbc?

 

[HT32BSX115]

Re: Another water in oil thread

Howdy D!



It's not likely your using automotive exhaust manifold gaskets would cause water in the oil. There's no path for water from the exhaust manifolds to the crankcase on a V-8 .

On the other hand, If you did not remove the risers and check the sealing surfaces and replace those gaskets it's possible that you could have water getting into the engine via open exhaust valves after you shut the engine down.


You would probably notice that the engine seems hydro-locked if enough water ran into the open valves. Then when you cranked it it's possible that it could force water past the rings and into the crankcase. I had a similar problem on my 460 and had a small amount of water getting in that way. The engine seemed hydro-locked if I tried to start it within about 5-10 min after shutting it down to retrieve a skier etc. If I left the engine off for 30 min or more it didn't seem to hydro-lock indicating that the little bit of water would leak past the rings etc.

I ran the boat this way for several days with no apparent ill effects.

The oil also did not seem milky at all.


The problem sounds an awful lot like a cracked block or head(s)


I would remove the risers and check the sealing surfaces and You probably should check the engines cooling system to see if it will hold pressure.


Regards,


Rick

 

[thrasher]

Re: Another water in oil thread

I would also try checking the compression on all cylinders to see if you have a failed head gasket. I doubt it's the automotive gaskets that are causing your problem (but it's also a bad idea to use automotive gaskets on a boat). There are not many ways water can get into your oil, the main culprits are condensation, bad manifolds, cracked block/head, failed head gasket. It sounds like you have been running your engine for short periods of time all year, so condensation is a real possibility. I would suggest drainig the oil into a clear container and see how much water is in the oil (the water and oil will seperate out if you leave it overnight). It does not take a lot of water to turn the oil milky. If you do run the engine on muffs, you need to run it for a long time if you are not going to be running on water later on. The whole engine needs to get hot (not just the cooling water getting up to temperature) otherwise you will get a lot of condensation inside the motor. Running a motor for a short period of time and then turning it off (and not using it for several weeks) is one of the worst things you can do to it, just because of the condensation.

Gary

 

[Robj]

Re: Another water in oil thread

I doubt that condensation is his problem, sounds like there is too much water for it to be conodensation. I would do a compression test first see what that says. Sounds like it is more likely a failed head gasket, or more likely a cracked block or head.

Have a great day,

Rob.

 

[Haut Medoc]

Re: Another water in oil thread

Pressure test the mans/risers,then the block.....
If you are lucky it will be the mans/risers that are bad.....
Cool avatar, btw......​

 

[wil7483]

Re: Another water in oil thread

I have a couple of questions for you guys. I removed both of the manifolds today after work and I can safely say that they aren't the culprits behind the water intrusion into the oil. Neither of them showed any of the so-called tell-tale signs of leakage. They were both sooty with no visible water lines or rust. I removed the elbows and they showed no rust buildup or blockage either.

So, my question is where else can the water be coming from? I checked the outside of the block real good and could find no signs of a crack anywhere. Plus, since the water appeared very slowly over the course of the season it had to be introduced gradually. Could it really be condensation? I'm wondering if rain / condensation could've gotten into the dipstick or carburetor. I have noticed that whenever it rains the inside of the doghouse is usually covered in a thick layer of condensation from evaporation. What else can cause water in the oil besides bad manifolds/cracked block?

Help me out fellas.

 

[wil7483]

Re: Another water in oil thread

if i was selling an engine, i might say that too.....

Yea, that's true but he was straightforward and very honest. I say this because I wanted the buy the whole shabang, engine, transom assembly, and sterndrive. He told me what was wrong with everything that he knew of and even refused to sell me the transom assembly because of damage to the gimbal housing.

some folks might be interested to know the year of yer 305 sbc?

1983

Okay, let me say this. I am not an engine guru so I will need some more help with this. How exactly do I pressure test the manifolds/risers? Also what all do I need to check the pressure in the cylinders?

 

[flabum]

Re: Another water in oil thread

Do you know the history of the engine? Where is it from? What state?


There are a few places water can get into the oil. The intake manifold can have a poor gasket seal, a cracked head or block, rotted intake etc......

 

[wil7483]

Re: Another water in oil thread

The Florida panhandle.

 

[achris]

Re: Another water in oil thread

I have a couple of questions for you guys. I removed both of the manifolds today after work and I can safely say that they aren't the culprits behind the water intrusion into the oil. Neither of them showed any of the so-called tell-tale signs of leakage. They were both sooty with no visible water lines or rust. I removed the elbows and they showed no rust buildup or blockage either.

Don't be fooled into letting the manifolds pass on a visual inspection. I was caught last week with a couple of manifolds that looked excellent. Still let water into the engine though. I used air and found the leaks, right in a spot where you couldn't see without a dental mirror. I pulled the engine and dropped the oil pan and cleaned it all out that way....

To pressure test the manifolds I cut a gasket to put between the manifold and the exhaust elbow (to block off the ports going to the elbow), removed the water hose from the thermostat housing and stuffed compressed air in... With the block and heads, I did them as one, I removed the water hoses from the bottom of the manifolds, plugged them with a bit of dowel and pressurized the engine by the incoming water hose. You'll hear pretty quick if there's a leak...

Good luck.........

 

[wil7483]

Re: Another water in oil thread

Did some more investigating today. I removed the valve covers and can see where water entered the head for sure from a faulty gasket on the valve cover screw off cap. The springs show signs of rust directly under the caps. Plus the fact that the water buildup was gradual over the season it stands to reason that this could surely be the culprit.

I will plug the openings in the manifolds/risers on Wednesday and fill them with compressed air and check for leaks just to be sure. The valve covers are ugly and beat up anyway so I will order some new ones also. Can I use regular automotive sbc chrome valve covers or are their some sort of special marine covers that I need to get?

 

[wil7483]

Re: Another water in oil thread

To pressure test the manifolds I cut a gasket to put between the manifold and the exhaust elbow (to block off the ports going to the elbow), removed the water hose from the thermostat housing and stuffed compressed air in.

I pressure tested the manifolds and they were fine, no leaks detected. I haven't figured out a way to do the elbows though.....any suggestions? Also, I wasn't all that clear on how to do the block and heads.

 

[achris]

Re: Another water in oil thread

I haven't figured out a way to do the elbows though.....any suggestions?

Usually the elbows are a visual and screwdriver test. The usual place elbows wear through is the very top of the exhaust path. With the elbow off the manifold and upside-down on the ground (or sturdy bench), use a strong screwdriver and try to punch through the metal. If you go through, it was about to anyway. Hitting solid metal and it all checking out on the visual, means it lives to leak another day.

Also, I wasn't all that clear on how to do the block and heads.

With the block and heads, I did them as one, I removed the water hoses from the bottom of the manifolds, plugged them with a bit of dowel. I removed the water hose that comes from the leg at the transom and used that hose to squirt compressed air into the block and heads.

Chris............

 

[wil7483]

Re: Another water in oil thread

I followed your advise with air and water and it did not demostrate any leaks, geysers, or hissing from escaping air so I am assuming that the block and heads are fine. I really do think it was the leaking valve cover oil fill caps that allowed the water into the engine. I am going to put it back together and refill the crankcase with oil and let it run for a few hours on the hose and see if the oil turns milky that way. If not I'll be certain that the problem has been found and I will then replace the valve covers and oil fill caps.

No one never did chime in and let me know if I can use regular automotive valve covers on it. I'm replacing the alternator, thermostat, and all the hoses while I have it out of the boat as well as have the carb serviced/rebuilt.

Thanks for all of the advise!

 

[achris]

Re: Another water in oil thread

No one never did chime in and let me know if I can use regular automotive valve covers on it.

As we don't get the 4.3 V6 here (in Australia) I have only ever used the genuine item. I do know that some of the one on the V8s don't fit as they interfere with the exhaust manifolds.

I'm replacing the alternator, thermostat, and all the hoses while I have it out of the boat as well as have the carb serviced/rebuilt.

Please, please make sure you use a proper marine alternator. We would hate you to become a space cadet.

Cheers,

Chris................

 

[wil7483]

Re: Another water in oil thread

As we don't get the 4.3 V6 here (in Australia) I have only ever used the genuine item. I do know that some of the one on the V8s don't fit as they interfere with the exhaust manifolds.



Please, please make sure you use a proper marine alternator. We would hate you to become a space cadet.

Cheers,

Chris................

Thanks Chris, yes it is a marine alternator. Also will go ahead and do the starter and coil. It's a 5.0Liter V8 SBC engine.

 

[achris]

Re: Another water in oil thread

It's a 5.0Liter V8 SBC engine.

Don't know why I was thinking V6... It states quite clearly in your signature that it's a V8 (at least I guess that what a 305 is )... Sorry about that... I guess the last one with bad manifolds, for me (2 weeks ago) was a V6 and I was still in V6 mode.

 

[Lakester]

Re: Another water in oil thread

hello,

---------------

Did some more investigating today. I removed the valve covers and can see where water entered the head for sure from a faulty gasket on the valve cover screw off cap. The springs show signs of rust directly under the caps. Plus the fact that the water buildup was gradual over the season it stands to reason that this could surely be the culprit.

--------------

i am wondering how water got to the area of the valve cover filler cap in the first place?? sounds as if this engine is sitting exposed to any rain that might fall? i may not be reading it correctly, but that is what it reads to me. sounds like it is not covered, or poorly covered, or wind blew cover. if it was mine, i would have an open or exposed engine covered well, and also have engine cover in place.

be sure ur gaskets at the corners of the head to intake mlfd (4 corners) are showing as they should be. at least for oe intake manifold gasket set the rubber gaskets that fit on the front and back to seal intake to lifter valley have rubber tabs. one set sits inside on lifter valley side and other is flat but exposed to the outside of where intake meets head. if not in place correctly, could indicate intake gasket(s) on head port side have slid.

also, be sure u torque ur intake manifold bolts correctly, in correct sequence and that eng threads in head are clean and bolts clean. torque to facotry specs. that bolt is a 3/8x24 NFC and i think it takes about 30psi on torque wrench. but double ck for factory spec.

i see no reason why automotive valve covers wouldnt work. a sbc is a sbc especially before 2000. are u thinking of a custom set in chrome or pol alum? usually only issue is routing accessories to accomodate the v/c change... if anything.

a cracked intake manifold below where the thermostat sits can cause water leakage into engine as can a pin hole thereabouts.

the timing chain cover to oil pan, if not set and sealed well will allow water into pan. as can back area seals by main cap seal. timing cover bolts and pan rail bolts should be torqued to factory spec. its in the in-lb range... i think they are 1/4x20 NFC for pan rail and 5/16 NFC for end bolts. timing cover is 1/4x20 NFC... unless later yrs and may be metric. but most mid 80s and earlier are all SAE threads.

it takes a lot of time and water to rust up a set of valve springs since they are so oily there as a rule. sometimes we get busy on other projects and so one gets neglected. may want to keep tabs that engine is not weather exposed.

hope u solve the problem. such matters can be quite frustrating.

regards

lakester

 

[wil7483]

Re: Another water in oil thread

The engine is covered by a doghouse but when it rains water collects in the bilge area and it then causes condensation all on the doghouse walls and the engine as well as it evaporates. Since it is enclosed it has no where to evaporate into the air so it just basically appears to be raining inside the doghouse onto the engine. The boat was not used but once all season and the rest of the time has sat in the yard. I probably started and ran it on the muffs 5 times or so throughout the year while I was working on it. I will tilt the boat at a greater degree from now on so that as much water as possible drains out the back when it rains. Another problem I have is that the inside of the doghouse is lined with sound dampening insulation with a thin aluminum backing or heatshield. That basically is letting the built up condensation fall right back down onto the engine. Like I said earlier, I will put it all back together temporarily and run it on the hose for a few hours and then see if the water reappears in the oil, If so then I have a bigger problem and will just search for a new engine. If not, I will finish working on it and try to get it back in the boat before March snapper season opener.