what does grey oil indicate?

[Peter O]

I looked at a boat I wanted to buy with a 3.0L Mercruiser. The lake test was fine, the motor checked out fine, (compression etc.) but the oil in the outdrive was very grey - almost slate colour. The seller said he changed the oil in the spring of 2001. What are the likely causes of the oil colour? How serious is it?<br />thanks

 

[Trent]

Re: what does grey oil indicate?

Sounds like a small amount of water is present. Worst case is a outdrive reseal. About 300.00

 

[12Footer]

Re: what does grey oil indicate?

Trent is right. It indicates water. It has a bad seal or seals. There are seals at the propshaft, driveshaft,shiftshaft or vent/fill screw gaskets..<br />Cost estimate is also right on.<br />Cost of doing it yourself (provided yu haver all necsarry tools) is around 40buks including lube refill.

 

[Peter O]

Re: what does grey oil indicate?

Thanks for that info. Is it possible it has anything to do with metal? The oil was grey in the upper and lower end.

 

[hondon]

Re: what does grey oil indicate?

I have to disagree with my esteemed bretheren on this.Grey oil in your gear case indicates at least some kind of abnormal wear.When you pull the bottom plug do you get a hairy ball of metal shavings on it?

 

[Trent]

Re: what does grey oil indicate?

He said Grey/almost SLATE. I agree that GRAY can be a problem.. Yes check the lower filler plug for CHUNKS of metal..Fine shavings (fuzz) is ok! It might be just a problem of me or how the color was described..SOrt of hard here on the net...

 

[Peter O]

Re: what does grey oil indicate?

There were no chunks of metal. The colour was quite dark grey and it was consistant throughout. I was surprised that the oil would go that dark in one season.

 

[12Footer]

Re: what does grey oil indicate?

Whoa,back up..You have grey oil in the uppper and lower end?? Do you mean the engine oil? Or do you mean the oil in the foot by the prop? Heck, all THREE of us may be off-base here.

 

[Trent]

Re: what does grey oil indicate?

Hey 12footer where you going with this..He said it was a 3.0 Mercrusier. AInt no way engine oil can get down there. I still think water is present in the outdrive from what he has said..<br />If I were him I would drain the drive refill and run it for a few hours and recheck the oil for color and metal..Just my thoughts<br /><br />PS Make shure you have good gaskets on your vent and fill plugs. Change them everytime. They cost about .50 or less.

 

[ODDD1]

Re: what does grey oil indicate?

I'll go with trent on this one...have seen this color before....buy a cheap gearlube, change it yourself, drop one of the fill screw gaskets/leave one on the end of the tube/double stack them on one screw and you get this color crud...used up oil with a small amount of water contamination....

 

[Hooty]

Re: what does grey oil indicate?

1) Stick a small pencil-size magnet in gray ca-ca.<br />2) Gently wash magnet in gas.<br />3) See what (if anything) iz left on magnet.<br /><br />c/6<br /><br />hooty

 

[petryshyn]

Re: what does grey oil indicate?

Ditto gents...<br />Seen it many times in gear boxes outside of marine.<br />>low level > more air in box > higher heat > <br />more oxidization > black oil<br /><br />What would be interesting is to use an ohm-meter to distinguish the difference between suspended aluminum and simply oxidized oil. Suspended aluminum would be quit low in resistance.<br /><br />just a thought......<br />

 

[Peter O]

Re: what does grey oil indicate?

To clarify for 12 footer, it is in the outdrive and the boat mechanic took off the screw down by the prop and then the cover at the top of the outdrive. Also, I did not buy the boat (yet) because I did not know the severity of the problem. Thanks to all of you I am beginning to think it is not too serious. Am I interpreting you correctly?The boat is 9 hours away at our "summer" place so I won't be able to check it out again until ******mas. Really appreciate your thoughts on this one as it was a "love at first sight" kind of thing. Also, I am very happy I took everyone's advice and had the inspection done even if I don't end up buying it. I highly recommend it for peace of mind and in this case, it made the decision not to buy much easier.