Yet another issue

[capthook]

Well I have just recently repaired a crack in my block (Yes It was winterized) that has been there for a while on the carb side right by the soft plugs. When I found this crack I checked the engine oil and it was perfect, almost like the day it went in. Well I ran the boat on muffs yesterday to make sure that the crack was sealed properly, and it was. I then went and did some general maintenance that I do whenever I am on the boat. Well I found a very slight hint of water in my oil and a oil leak that looks like it is coming from the head to the manifold right at the rear of the head towards the exhaust riser. I drained the oil from the motor and it come out looking like oil with vanilla swirls (Very light swirls). This is a 1973 GM inline 4 with the mercruiser one drive. I guess I am looking for some insight into where to start. I unfortunately don't have any pressure testing tools but have worked on this boat from the day I got it about two years, so I know my way around it fairly well. Any help! Thanks everyone.

 

[capthook]

Re: Yet another issue

Anyone?

 

[Haut Medoc]

Re: Yet another issue

If you have water in your oil, you either have a cracked block, intake, or leaking exhaust manifold/riser or the joint between them....
Run the engine, pull the plugs right away & check for water.....
On an engine that old a leaking manifold could put water in your combustion chamber & seep past the rings into your oil while the engine sits......​

 

[Windykid]

Re: Yet another issue

I guess you need to do a compression test.

Probably need to pull the head and replace the head gasket.

 

[capthook]

Re: Yet another issue

I am going to tear down the manifold and take off the head and inspect the gaskets. That was my first guess was bad gaskets. The boat is so old it may have not had the gaskets replaced in years. What is the life span of a gasket for manifolds and heads of marine nature? I have had the boat for two years now and have not replaced them. Thanks again.

 

[Coors]

Re: Yet another issue

Why not pressure test it first?

 

[capthook]

Re: Yet another issue

I don't have the tools to do this, or I would. Also I feel pretty confident that it is a gasket. I like to lean towards the ironic parts of things. Like how I just started leaking oil from the manifold/head area and now I am getting a little water in my oil. I really think that it is a gasket issue.

 

[Haut Medoc]

Re: Yet another issue

Like I said, I'd suspect the exhaust system of a leak before a head gasket......
Pull off the riser & inspect the mating edges.....
Any rust on the interior?.......​

 

[capthook]

Re: Yet another issue

Who online has the best prices for gaskets? Mercstuff? or here at Iboats>

 

[whywhyzed]

Re: Yet another issue

I don't have the tools to do this, or I would.

a hose clamp and a bicycle tire pump

 

[capthook]

Re: Yet another issue

Ok so here is what I have done. I changed the oil and also put some sea foam in the crankcase as well. I let it run a while on the muffs and then changed the oil and filter. When I changed the oil the water look was barely noticeable. So I then put in more oil and a new filter. My oil looks really well on the dip stick after running it another 45 minutes on muffs. Would I be able to tell if there is water in my oil by looking at the dip stick? The oil is so clear I can almost see my reflection. Thanks! Johh

 

[cmcpherson]

Re: Yet another issue

You keep posting on this subject and pretty much ignoring the advice that you are being given???

 

[cheburashka]

Re: Yet another issue

I agree with Cmcpherson--you need to pay more attention to the advice you're getting. I have the same problem sometimes. I don't like what I'm hearing here, so I keep asking the same questions until I get an answer I like. Sadly, that can lead you to bad repairs, like when the answer I liked came from someone who said you don't have to winterize a 3.0 Merc. Saved me a couple of hours and cost me a lot of money and a lot of time.

You have a water leak. You need to find it. The reason it's leaking now is that you sealed up the biggest hole in the block and now there's more pressure in the block and the water is finding another exit. Taking off the head won't tell you where the leak is. It could be a porous head casting, a manifold leak, a cracked block, or any number of other things. You need to pressurize the block to rule out the head and the block. You can do this with the manifold off or on, but do it before you pull the head.

Easiest way to do it: Get a bicycle tire pump with a built in gauge. Disconnect the inlet at the thermostat housing and connect the bicycle pump head at the inlet using a short piece of hose. Lock it in place with a hose clamp. Another option is the put a car tire valve into the hose and lock it in place. I think that gives a better seal. Block off the exit to the manifold with a screwdriver handle or something similar. Pump it up to 15 pounds with no water in the block. Listen for leaks. If you don't hear any, wait fifteen or twenty minutes and check the air pressure again. It should hold pressure the whole time. If it doesn't, fill the block completely with soapy water, then pressurize it again. Watch for bubbles. It's a simple test, but it tells you a lot more than you'd find out from pulling the head.

When you pull the head rust tracks might tell you where the leaks are, but don't count on it.

 

[whywhyzed]

Re: Yet another issue

Only thing I can add to the above procedure is that you'll also need to take the hose going to the exhaust manifold off at the manifold, and put a 5/8" bolt in the hose and clamp it in order to build pressure in the block, other wise as you pump air int, it will just go out the exhaust riser.

It's really quite easy to do.

 

[whywhyzed]

Re: Yet another issue

I just remembered I made a little video of testing a 3.8 block. I will put it on youtube.
I used an air regulator and shop air instead of a bicycle pump but basically you would do the same thing. You'll see how I blocked the lines to the manifolds with plugs.

http://www.youtube.com/watch?v=yJQIjafvZjc

I had bought this 3.8 on eBay that was cracked inside - the seller eventually refunded approx. 90% of my money when I showed him this video, and another clip of water draining out the pan. He told me they put water in to claim it on insurance and that I should just change oil and go... why the hell he would say he had committed insurance fraud when he hadn't is beyond me. Later I pulled the intake off and sure enough there were tons of cracks in the block above the lifter galleries on both sides. Worked out better for me anyways because I have lots of 3.8 's around. One manifold was good....one bad.... it had been advertised as a good running engine.

 

[capthook]

Re: Yet another issue

You keep posting on this subject and pretty much ignoring the advice that you are being given???

I have made a leak tester here at work, just got done 10 minutes ago, that is why I have not taken the advice and let everyone know the results. If I can make a nice "Multi use tester" for free instead of going out and buying one sounds good to me. I have made this tester so I can change fittings and test the compression as well. When I get off work I am going to do this. Also thanks for the video I appreciate that very much. Thanks again to all that are helping.

 

[capthook]

Re: Yet another issue

Ok here is what I have. I did the pressure test and could not hear any leaks but the gage was very very very slowly going down it took maybe 10 to 15 minutes to go from 15 psi to about 8 psi. I put soap and water in and did the test again. I could not find any place that was leaking still and the gage did the same. So I went out and got a factory gage. Still the same thing. I also did this without starting the motor first and letting it warm up. I also checked the compression here are those numbers, 1= 115 Cold, 2= 110 cold, 3= 113 cold, 4= 118 cold. Here are the numbers after letting it run up to operating temps, 1= 118 hot, 2=115 hot, 3=117 hot, 4=120 hot. I did not do the engine pressure check while it was hot due to the big yellow ball of fire in the sky getting tired on me. So I checked the oil after running still looks great and the level has not changed at all. I know that being under load is a different story, but I let it run for about 30 minutes. What does every think? I will be patiently awaiting your replies.

 

[capthook]

Re: Yet another issue

any advice on where I should go from here?

 

[capthook]

Re: Yet another issue

Where should I go from here?

 

[capthook]

Re: Yet another issue

bump