Oil color question

alexr254

Petty Officer 1st Class
Joined
Jun 21, 2011
Messages
262
Hello All.

I was recently given a Mercruiser 470 3.7 ltr which i was told has roughly 20 hours use on it.
It has been stored for a couple years in one of those self storage closets.
The engine itself is a bare bone, it is the engine block and head only, without any manifolds, carb, etc... just the core engine with the block/head/oil pan.

The rest of the parts I have on a old same model engine which overheated and will salvage the parts. I will replace it with this new one once rebuilt.

Just yesterday i went and and put it up on the engine stand and pulled the oil drain plug... I was surprised to see a somewhat greyish oil come out with the consitency of diesel oil, but the color was a consistant grey (a smokey color). :confused: :confused:

After reading up on it, i am aware that its most likely water in the oil. But can it possibly be some sort of storage oil regent or something?

I have yet to remove the head from the engine, but will probably do it tomorrow to change the head gasket. Its just strange that a hardly used engine would have a bad head gasket, or water in the oil when it was stored indoors.

Or maybe i was lied to. :mad:

Any ideas what it could be?
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,357
Re: Oil color question

Or maybe i was lied to.

Ayuh,.... I'd bet on That....

Gray oil is usually Water contaminated...
 

90stingray

Lieutenant Junior Grade
Joined
Oct 26, 2010
Messages
1,162
Re: Oil color question

I would bet you were lied to... that's prolly why it was given to you. At least you didn't pay for it.
 

JWebber

Petty Officer 2nd Class
Joined
Oct 21, 2008
Messages
137
Re: Oil color question

It could be also from condensation from sitting open like that. My gues would be to open it up or flip her over on a stand.
 

Alumarine

Captain
Joined
Feb 22, 2005
Messages
3,757
Re: Oil color question

Colors are hard to determine on the internet.
Can you provide a picture?
Oh, and welcome.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Oil color question

Milky gray is the color of some oils with water in it. A lot more water than just condensation.
 

Fordiesel69

Lieutenant Junior Grade
Joined
Sep 18, 2009
Messages
1,146
Re: Oil color question

Who cares about the oil color. You will still need to properly inspect / rebuild before putting in your boat.

Never beleive the story about its past. 9-10 times it is a lie.
 

alexr254

Petty Officer 1st Class
Joined
Jun 21, 2011
Messages
262
Re: Oil color question

There is no doubt i will change the gasket and take the head to the shop to have it cut.

Also there is no doubt water was in the oil, i placed some in a cup and let it sit for a day and noticed the oil on top.

I am still unsure how it got in there, but regardless will do an entire revamp.

thanks all.
 

alexr254

Petty Officer 1st Class
Joined
Jun 21, 2011
Messages
262
Re: Oil color question

its all good. i kinda knew what i was getting into, replacing an engine. But this was a surprise, that the replacement engine is basically shot.

Took the head off, looks like one of the pistons has some damage. Looks like it was banging against a little pebble and has small dents all on the top. i poured some oil on top to see if it leaks.

I am getting the head recut and will probably need to do an entire rebuild.
 
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