4.3 LX Water in oil
 

Have a 1993 4.3 LX. Removed and replaced head gaskets, exaust manufold gaskets, intake mainifold gaskets, had the heads and intake manifold magnifluxed for cracks. reassembled and still getting water in the oil. Other than an internal crack with the engine block, what else could it be and is cast iron weldable?

Re: 4.3 LX Water in oil
 

Did you have the exhaust manifolds checked for cracks? Chances are very good they are cracked internally if the entire engine was not winterized properly.

If they were checked, then your block is cracked internally and must be replaced.

Re: 4.3 LX Water in oil
 

Would a cracked exhaust manifold put water in my cylinders too?

Re: 4.3 LX Water in oil
 

The left exhaust manifold has a slight fracture on the outside and bleeds water over a period of time.

Re: 4.3 LX Water in oil
 

Yes... Every time the engine is turned off, water will flow into any open exhaust valve, and into the cylinder. If it is cracked on the outside, 100% it is cracked inside as well.

Install new manifolds and risers, and you should be ok.

Re: 4.3 LX Water in oil
 

I have no water contamination in the cylinders they are all dry. I did have a frost plug leaking on the left side of the block a couple of years ago. The Water in the oil started some time after that. The engine runs smooth that tells me there is no water getting to the cylinders. Is there an easy way to pressure check the intake manifold?

Thanks

Re: 4.3 LX Water in oil
 

With cracked manifolds, the engine will run just like normal. The escaping hot exhaust blows out any water that may be present. It's only after the engine is shut down, does the water flow into the cylinders through the exhaust valves. Once there, it will seep by the rings and drain into the oil pan.

To check for internal cracks, you need to pressurize the cooling system with air, just like on a car radiator. Not easy to do on a marine engine, but it can be done. Drain the entire cooling system of any water, then plug/ clamp off every hose, including the ones going to the exhaust manifolds. Pump it up to 15 PSI and see if it holds.

Re: 4.3 LX Water in oil
 

Thanks for the info 300sflyer. The last time I changed my oil I ran the boat on the lake for about 20 minutes. I opened the oil filler cap and found the oil was extremely milky white. The engine ran fine could this still be an exhaust manifold?

Thanks

Re: 4.3 LX Water in oil
 

Before you spend any money on new manifolds and risers, test the block with air. If you think it is holding, then change out both manifolds and both risers, and do an oil change. Let it run with your garden hose and muffs for 15 to 20 minutes, at full operating temperature. [Just at idle] Stop the engine, and check the oil for color and to see if it is any higher on the dipstick.

If all looks good, then head out on the lake and run the boat at crusing speed for15 minutes or so, and check the oil again. Don't stray too far from the launch ramp though... Sometimes internal block cracks do not leak, until the engine is fully heated up, and run under load.

Good luck!

Re: 4.3 LX Water in oil
 

If I understand you, you changed the oil, then headed out to lake without running it on the muffs? Did you stop the engine at all during those 20 minutes? How much higher was the oil level after the 20 minute run?

Re: 4.3 LX Water in oil
 

The last repair I did to the engine was replacing the head gaskets, intake gaskets, exhaust manifold and riser gaskets. I also replaced the thermostat too. I put the muffs on and ran the engine for about 45 minutes. I had the oil filler cap off to observe any water mixing with the oil. After 45 minutes of running the engine at 1500-1700 rpm the oil did not turn milky color. I then took it to the lake ran it for about 20 minutes at 4000rpms. I then stopped the boat and let it idle while I opened the oil filler cap. The oil in the valve cover was extremely milky white. Again the engine ran smooth.

Thanks again

Re: 4.3 LX Water in oil
 

Was the oil level on the dipstick higher after running the engine on muffs or out on the lake? If so, when, and by how much? Sometimes it can take 2-3 oil changes to remove all of the water.

Given everything you have stated, I would say there is a very good chance your block is cracked. However untill you do a pressure test, there is no way to know for sure short of tearing the engine down completely, and having the block itself magnifluxed.

Re: 4.3 LX Water in oil
 

Running the engine with the muffs on did not change the color of the oil. Running the engine on the lake at a high power setting for 20 minutes turned the oil a milky color and added about a quart or better of water to the oil pan. It appears I may have a crack in the water jacket not visible from the exterior.

Re: 4.3 LX Water in oil
 

Agreed... Do the pressure test, or pull the engine and tear it down completely to comfirm.

If it was me, I would find a new short block, and transfer everything over from the old engine. DO NOT reuse the existing exhaust manifolds and risers.... Buy new ones.

Re: 4.3 LX Water in oil
 

I'll post what I found with the engine when I get it apart. How difficult is removing the engine?

Thanks again for the additional info.

Re: 4.3 LX Water in oil
 

It can be quite difficult, depending on the amount of space available to get at the engine itself. I would highly recommend you consult an OEM service manual for both your engine and drive.

mercruiser service manual - 4shared.com download free

You will need some kind of engine crane to lift it out once everything is disconnected. An automotive engine crane does not usually have the ability to lift it high enough to clear the back of the boat. Here is how I solved that problem, if you do not have access to a fork lift or some other means of lifting it.

http://img.photobucket.com/albums/v6...r/DSC_0330.jpg

Re: 4.3 LX Water in oil
 

One last piece of information before I remove the engine. I have had the intake mainifold of three times since I started trouble shooting the water in my oil. As I stated before each time I ran the engine on the lake the oil as seen through the oil filler cap was almost foamy white. The two times I removed the intake manifold and the valve cover with the oil filler cap the oil in these areas were milk shake white. I took the other valve cover off ,it had only a trace of water not enough to be milky white. Can anyone explain. See attached link this is what my engine looked like.

YouTube - Mercruiser 4.3, Blown Head Gasket

Re: 4.3 LX Water in oil
 

Can't say for sure, but I'm betting once it is taken apart, you will have your answer.

Re: 4.3 LX Water in oil
 

I have a 93 mercruiser 4.3 and i have same problem with water in my oil.
Was it a cracked block? Or something else please let me know.

Thanks PJ

Re: 4.3 LX Water in oil
 

First ..... Welcome to MOC! :)
Second , it would probably be better to contact the poster via email or PM him.
This thread is over 2 yrs old.
You might want to start a new thread with all , and any info you can think of on "your" problem.
It could be cracked block , heads , exhaust manifolds , intake gaskets , exhaust flappers , the list goes on and on.:(

Once again welcome , and sorry to hear of your problem.