Water in oil, could this be the issue?

[bulletfever159]

I had a lot of water in the oil pan when I drained with an oil extractor. I left the boat drain plug in and it had rained a ton in central florida causing half of the motor to be submerged. It sat like that for about a week or so before I noticed. The boat has never been ran hot other than one exhaust riser being a little hotter than the other but not an extreme temp. I know the engine should be sealed but anyone have any thoughts?

 

[bulletfever159]

2001 Mercruiser 4.3l

 

[Scott Danforth]

Most likely its bad exhaust manifolds

However if you had the plug in and water got as high as you say, your starter is now junk, or will fail very soon, and if the alternator was under water, that will fail too. So will any wire harness that was under.

Doubtful water got in the crank case unless water was up to the top of the engine

 

[bulletfever159]

Most likely its bad exhaust manifolds

However if you had the plug in and water got as high as you say, your starter is now junk, or will fail very soon, and if the alternator was under water, that will fail too. So will any wire harness that was under.

Doubtful water got in the crank case unless water was up to the top of the engine

Yes, you are correct. My starter was junk so I ended up replacing it. I have had to replace a lot of wires and switches lmfao. But would a bad exhaust manifold cause water to get into the oil pan? I’ve cycled two things of oil through it and it’s definitely thickened up like oil but it’s still creamy color (figured it would probably still be pretty creamy). I put four and a half quarts in and got out 4 and a half quarts after running it for about 15 minutes

 

[Scott Danforth]

If you boat in salt water, exhaust manifolds last only 7-10 years max.

The manifold to elbow gasket joint fails and leaks water down the ports

Not to mention the intake manifolds rust thru

 

[bulletfever159]

If you boat in salt water, exhaust manifolds last only 7-10 years max.

The manifold to elbow gasket joint fails and leaks water down the ports

Not to mention the intake manifolds rust thru

Here’s a couple pics, they were pretty beat up. I was planning on replacing them and that’s when I found the watery oil and decided to try and diagnose that before throwing another 1k into it

 

[Scott Danforth]

That first pick is the smoking gun

New manifolds and elbows should only cost about $550

 

[bulletfever159]

That first pick is the smoking gun

New manifolds and elbows should only cost about $550

Thanks for the replies, I also have the spacers so all in all costs around 650ish per side all Sierra parts. Hopefully get everything installed and see how it does on the water.

 

[Scott Danforth]

Dont use sierra. Use either mercruiser or Barr

 

[Bondo]

Yes, you are correct. My starter was junk so I ended up replacing it. I have had to replace a lot of wires and switches lmfao. But would a bad exhaust manifold cause water to get into the oil pan? I’ve cycled two things of oil through it and it’s definitely thickened up like oil but it’s still creamy color (figured it would probably still be pretty creamy). I put four and a half quarts in and got out 4 and a half quarts after running it for about 15 minutes

Ayuh,..... Not while the motor is running,.....
Only while sitting, as it takes time for the water to seep past the rings,....

 

[bulletfever159]

Dont use sierra. Use either mercruiser or Barr

Is there a specific reason why? I thought Sierra was a good brand.

 

[Bondo]

Is there a specific reason why? I thought Sierra was a good brand.

Ayuh,.... They sell rebranded chinese manifolds,....

I had a set of GLMs that needed to be machined flat, when brand new,....

 

[Lou C]

I installed a set of Barr manifolds 4 seasons ago and they fit perfect with no leaks.

 

[bulletfever159]

Looks like I’ll be canceling and returning the Sierra ones, thanks for the insight!

 

[Lou C]

Before you install them check the mating surfaces with a straight edge and feeler gauges, mine were flat to less than .001"
If you are in salt water I'd put a better coat of paint on them because the OE paint is thin. I just brushed on a couple of coats of rustoleum. The manifolds don't or shouldn't get that hot so it works fine.
I used their gaskets + Permatex Aviation.

 

[Scott Danforth]

Is there a specific reason why? I thought Sierra was a good brand.

because Sierra is generally Chinese junk. Mercruiser gets half of their manifolds from Buddy Barr castings. So you cannot go wrong with her Factory Mercruiser, or Barr castings.

The gaskets that failed on you leading to water intrusion are known as Sierra green leakers.