Logo
FULL SITE MENU

Need help with 3.0l 181 cid water leak

C

cubajorge2008

New member
I'm new to the boat world. and I'm trying to repair a recent issue that i encounter. waters seems to be coming from the back of the engine inside the boat. let me show a picture of what i mean. I'm trying to figure out what could be the issue and how to fix it. old-merc-drive-transom-serial-number-locations.jpg I will throw a picture of the engine itself now but this is a diagram of where waters is coming from
 
If not caused by seawater pump suction hose, it may be coming from a rear casting core plug (aka welch plug).

Just ahead of the flywheel you will have two casting core plugs.
If the engine is Raw Water cooled, one of these welch plugs may be rust compromised.
The automotive engine would have steel plugs, whereas the Marine version would have brass plugs.

Do you see the leak only when the engine is running?

3.0L GM rear .jpg
 

Attachments

  • SBC rear casting core plugs.jpg
    SBC rear casting core plugs.jpg
    19.2 KB · Views: 217
Last edited:
I only see the leak when the engine is under load. not with the water here is the picture where the problem is 0.jpg. Alot of waters come thru there when under load. I see the picture you send me. what will be the fix if it is complete rust?
 
Last edited:
Your first image looked like a V-8. Your second image is clearly a 3.0L GM.
I just changed the photo to a 3.0L GM 4 banger.

If the plug is rusted and is leaking, the only fix will be to remove the engine and replace the plug.


.
 
Last edited:
Rick, stay away and go to volvo penta where you belong.
Your pic is of a V8. Wrong image and will only add confusion.
3.0 ltr is a 4 cyl....ugh
Question to boat owner, how much water is in bildge under engine?

Your pic is difficult to pin point water.

Also when you say under load you do mean while in the water and not on a trailer??
 
.....................
kghost said:
Rick, stay away and go to volvo penta where you belong.
Your pic is of a V8. Wrong image and will only add confusion.
3.0 ltr is a 4 cyl....ugh

Jack, go back and look at the image again! Put your eye glasses on if need be!
Also, read post #4 again where I mentioned that I changed the image due my looking at the OP's first image that shows an exhaust manifold on the Starboard side.


Question to boat owner, how much water is in bildge under engine?

Your pic is difficult to pin point water.

Also when you say under load you do mean while in the water and not on a trailer??
Under Load typically means "Under Load" .... as in the boat is IN the water and the ENGINE is working to turn the drive!
Sheesh!
Click to expand...


Cubajorge, my apologizes to you for Jack's behavior.
He appears to be suffering from a condition that causes a not-so-pleasant forum attitude, and also causes him to believe that he has exclusive Merc section rights.
This has been going on for some time now!


.
 
Last edited:
thank you guys for all the replies yeah water is splashing out from the rear cover. now to challenge is lifting up the engine to change the plug. or is it possible to do it without taking it out?
 
No

Engine has to come out to remove bell housing/flywheel cover to access core/freeze plugs.

Drive has to be removed

then all electrical connections to engine, cables, fuel line, Exhaust hose (large coming off elbow), shift bracket or cables which ever is easier, incoming water hose then motor mounts. Engine should have lifting rings already installed. use a good chain that will clear everything when tension is applied.

Hope that is your issue as you didnt answer mine question about water in bilge
 
RicardoMarine said:
.....................



Jack, go back and look at the image again! Put your eye glasses on if need be!
Also, read post #4 again where I mentioned that I changed the image due my looking at the OP's first image that shows an exhaust manifold on the Starboard side.


Question to boat owner, how much water is in bildge under engine?

Your pic is difficult to pin point water.

Also when you say under load you do mean while in the water and not on a trailer??
Under Load typically means "Under Load" .... as in the boat is IN the water and the ENGINE is working to turn the drive!
Sheesh!


.[/COLOR]
Click to expand...

I dont care about your second image or your post 4.

I also dont care about your opinion about "being under load"

What would you know what the poster means? Most who post say/use the wrong descriptions all the time. He CLEARLY states he is new to the boating world, unlike you with so much and vast experience answering questions in a forum you dont belong in.
 
You remove the drive first, then lift the engine up enough to remove the rear housing, coupler, flywheel and see if it is just a core plug or a cracked block. This should leak in the water or on a trailer
 
OK. so i remove all parts needed. lift the engine did all the things i needed and the core plug was intact no issue to it to the visible eyes. i still went ahead and replace it. . Tomorrow i will take it to the river and just keep it on the trailer until i see visible water coming in and try to figure out where the water is coming from exactly. if there is a water leak should it happen on the trailer as well? maybe i didn't let it get hot enough so that water circulates on the entire engine? i will try all i can tomorrow and come back with results.
 
You could have introduced water into the engine to check for leaks first simply by removing the large hose from the T stat housing and stick a garden hose in there
 
Alright so i put it with the hose let it warm up and yup water is coming in thru the exhaust elbow. And this seems to be my replacement [FONT=&quot]GLM Part Number: 51160;[/FONT]
 
Never heard or seen a elbow leak unless it has a freeze crack or the rubber coupling was split. In your pic you show the stbd side of the motor that is opposite of the side with the exaust. Water from a leaking exaust cant fly up and over? And if its coming from the flywheel /starter area its not the exaust
left a message
 
cubajorge2008 said:
Alright so i put it with the hose let it warm up and yup water is coming in thru the exhaust elbow. And this seems to be my replacement [FONT="]GLM Part Number: 51160;[/FONT]
Click to expand...

I think someone needs a new pair of glasses....
A lot of work for a leaking exhaust.....ugh....

Look in craigslist for used boat parts, fresh water use only, and see if you can find a cheap replacement.
If not, try this site for new Mercruiser replacement.
 
Back
Top