Does my oil look 'water contaminated'?

[deerhuntre]

I just drained the oil from my Mercruiser 165 inline 6. Does this look like water intrusion from a cracked block? The previous owner told me he did not do an oil change before storing the boat for the winter.

 

[alilley]

Re: Does my oil look 'water contaminated'?

i have had experances with water in the oil due to a cracked block. and the best way to explain what it looks like is go to wendy's get you a frosty and lt it melt.

i did a fresh oil change in my boat (had a mercruiser 3.0 inline 4) had very little run time on it talking less then thirty mins and that is what it looked like. so i drained it (did not change filter) put fresh oil in it just to get it over to the trailer and sure enough it looked the same again. after tearing it down noticed a cracked block and head and a blown head gasket.

me personally it dont look like it has that much water in it if it does but if it dont then that oil does not have a hole lot of run time on it as it is still carmel color

 

[Dieter]

Re: Does my oil look 'water contaminated'?

I would say yea. Just had the same problem . I changed mine twice and I ran the engine for about 10 mins for it to get hot then opened the oil cap and let the moisture come out as well. It drove it on the lake for about an hour opening it several time in that span. Not doing it anymore. Good luck .

 

[wifisher]

Re: Does my oil look 'water contaminated'?

Yes, there is water in it. Does not mean it is a cracked block. It could be a head gasket, intake gasket, cracked block, cracked head, cracked manifold, etc. Bad block is far from the only place to get water. Check it over before you condemn it.

 

[deerhuntre]

Re: Does my oil look 'water contaminated'?

Thank you for the ideas. I did a compression test and that came out perfect. All cylinders the same and around 130 psi.

Would I be able to see a crack from the outside? I took a bright light and went around the engine as best as I could and didn't see anything. I'm thinking starting with easiest to hardest: Pull exhaust, pull heads, examine, replace gaskets. Is this a good approach?

 

[wifisher]

Re: Does my oil look 'water contaminated'?

You can't see a crack from the outside all the time. Very rarely actually. You would be best served to pressure test the cooling system. Just replacing parts and hoping it works can get very spendy.

If you are not familiar with pressure testing, you can search the forums for it and find plenty of threads about it.

 

[deerhuntre]

Re: Does my oil look 'water contaminated'?

That's true. I've been reading about the pressure testing on here a little bit, thinking that may have to happen. I'll set aside some time for the testing and continue this thread with results and go from there.

 

[Joshua Nichols]

Re: Does my oil look 'water contaminated'?

You wanta pressurize the cooling system.Not so much the cylinders. Takes a bit of rigging( I should make a kit and sell it on E bay). Some large dowel pins and a air compressor is a good start..

Check the exhaust manifold.. You forsure have water getting in the oil.. Got a bucket of the same looking stuff in my garage

 

[deerhuntre]

Re: Does my oil look 'water contaminated'?

So does this sound correct for pressure testing:

Pull the lower unit, plug the intake.
At the front of the motor, detatch and plug the hose going to the exhaust manifold.
Detatch the skinny hose running along the top of the motor and plug at the thermostadt housing.
Attatch a fitting to the hose that was detatched from the exhaust with an inline guage of some sort.
Fill with air from compressor/pump. Detatch, close and wait.

I did some searching and found a lot of stuff for outdrive pressure testing. Only a bit for this.

Oh, and before I do all this, I will run on my fresh oil in the driveway and see if I get any new water.

 

[HT32BSX115]

Re: Does my oil look 'water contaminated'?

Pull the lower unit, plug the intake.

No.

Just disconnect the (raw water supply) hose from the transom to the t-stat housing.

All you're doing is plugging the water input, output and isolating the exhaust manifolds from the cooling system

 

[deerhuntre]

Re: Does my oil look 'water contaminated'?

Well, I ran the motor on the hose with fresh oil/filter and there is most definitely water getting into the oil. So, on to the diagnostics!

HT32BSX115, I took a look just now and this makes more sense. Thank you.

 

[Bondo]

Re: Does my oil look 'water contaminated'?

and there is most definitely water getting into the oil. So,

Sooo,... In your search for another motor,...
Be aware you need 1 with the little boss cast onto the starboard forward corner of the block...
some automotive blocks don't have it...
Some Do...

I believe Fishermark built a work-around for it,.....

 

[deerhuntre]

Re: Does my oil look 'water contaminated'?

Thanks for the heads-up on the boss....however, from what everyone is saying, this motor may or may not be toast, correct? Doesn't it depend on what the cause is for the water intrusion? Or am I wrong in my take-away from the discussion and resources?

 

[HT32BSX115]

Re: Does my oil look 'water contaminated'?

Thanks for the heads-up on the boss....however, from what everyone is saying, this motor may or may not be toast, correct?

Do the pressure check. During this time of year, 99.999% of "water-intrusion" into the oil IS due to a cracked block.

Don't make any decisions until you know for sure. The pressure check will tell you!



You shouldn't have a Lot of problems finding the right engine. I have a pickup wrecking yard down the road and when I was looking for a 250 cu-in 6 for my previous boat, they had about 15 of them. (5 or 6 of them had the correct front mount point for a Mercruiser mount)


Good luck.



Rick

 

[deerhuntre]

Re: Does my oil look 'water contaminated'?

What I just found out: I contacted Cruiser's, Inc. and they told me, according to my SN, my boat originally came with an OMC 165! Since it currently has the Mercruiser 165, it seems that it was repowered along the way!! So, now I'm really curious to find out how old this motor is. Anyhow, I did not get to pressure test the cooling system this weekend but hope to get to it one day this week. Thank you again for all you help and I'll update as soon as I get to it.

 

[deerhuntre]

Re: Does my oil look 'water contaminated'?

Pressure test results:

The cooling system held 15psi. There were no audible 'hissing' sounds or any other sign of leaks. Does this mean my block is probably OK? I have just received my new head and manifold gaskets, so I'm going to change those out and inspect everything as I take it apart. Please let me know your thoughts and suggestions at this point.

 

[90stingray]

Re: Does my oil look 'water contaminated'?

Pressure test results:

The cooling system held 15psi. There were no audible 'hissing' sounds or any other sign of leaks. Does this mean my block is probably OK? I have just received my new head and manifold gaskets, so I'm going to change those out and inspect everything as I take it apart. Please let me know your thoughts and suggestions at this point.

Held 15 psi for how long? I sure wouldn't shotgun parts at it unless I knew what was wrong.

 

[deerhuntre]

Re: Does my oil look 'water contaminated'?

How long do I need to test it for? I did five minutes.

 

[90stingray]

Re: Does my oil look 'water contaminated'?

I would say 30 minutes... minimum.

 

[petermarcus]

Re: Does my oil look 'water contaminated'?

Just a thought, but is it an I/O? The exhaust after the manifold, but before the outdrive, has a one-way flap to stop water from backing up into the engine. It's possible that there's a blockage or a bad flap there and water got up through the exhaust pipe and dumped through the manifold into the engine.