Weird Gear Oil

[davemoore]

We had our boat out today after doing a bunch of service work on it over the past 2 weeks, including a new impeller, new shutter, new coolant, new oil, and new gear oil. It ran really great, and stayed at about 150 degrees all day.

When I bought the impeller kit at the Mercruiser dealer, he sold me synthetic gear oil (for just $14.00 a quart) and said it was the best and to only use synthetic. Since he's been working on boats since the mid-70's, I figured I could trust him.

The synthetic oil is Sierra Marine brand, and is clear. The oil that came out was black (old?).

I opened the drain plug to just check it tonight, and the few drops that I got out were still clear, but there were little weird specks of black in the oil. I took another sample and it had the same black specks. I rubbed the specks between my fingers and they didn't appear to be hard (like chunks of anything), but they didn't break up either.

Could this be the old oil and new oil not liking each other? I've NEVER been a fan of synthetic oils... Should I drain it out and go back to regular gear oil?

Please help... anyone?

Thanks,

DM

 

[Fun Times]

Re: Weird Gear Oil

What style and name brand drive do you have? more then likely it is the too oils mixing a little,[New & old] But It really is not a good idea [IMHO] To keep changing oil brands, I am a belever in once you pick your style oil from newer try to stay with it till the end, And on gear oils to me is, Use the manufacturer's gear oil only. And on engines use a good name brand and stay with it.

 

[fabrimacator21]

Re: Weird Gear Oil

I don't know exactly what the impeller looks like but I know it's rubber. Could that possibly be wear from the impeller?

 

[mkast]

Re: Weird Gear Oil

I've NEVER been a fan of synthetic oils...

Why?

 

[Bt Doctur]

Re: Weird Gear Oil

Unless they changed the formula, synthetic is a greenish colored and dino is a honey color. You sure it`s not clear power steering fluid you were sold.

 

[Maclin]

Re: Weird Gear Oil

Synthetic outdrive gear oil is designed to hold contaminants in suspension, especially water. It can take on a lot more water and still lube the drive so for outdrive applications it is really worth it.

I am not sure what the black specs are but my gut feeling is that you are right on the new oil responding to the old oil.

Were you able to see what they drained out from their service?

 

[Don S]

Re: Weird Gear Oil

Unless they changed the formula, synthetic is a greenish colored and dino is a honey color.

Not exactly. Merc Hi Performance gear lube is green, Volvo Gl-5 Syntheatic gear lube is honey color.
The green color is just Mercs addatives.

 

[Don S]

Re: Weird Gear Oil

Unless they changed the formula, synthetic is a greenish colored and dino is a honey color.

Not exactly. Merc Hi Performance gear lube is green, Volvo Gl-5 Syntheatic gear lube is honey color.
The green color is just Mercs addatives.

Water will mix with the Hi Performance, and become milky. The water will seperate from the Volvo GL-5 Synthetic.

 

[davemoore]

Re: Weird Gear Oil

I did the work myself. The drive is Mercruiser Alpha I.

I drained all of the old oil out, which was quite black, and then pumped the new oil in from the bottom until it came out the top vent hole.

Here is the oil I put in:

I guess it is kind of a honey color... not clear.

I suspect what I'm seeing is little specks of the old oil suspended in the new oil... that would make sense.

It is definitely not milky.

 

[bigskiohio]

Re: Weird Gear Oil

that is not the mercruiser syn. the + if i remember right and it is green
i paid 15.00 a quart ,sierra is not mercruiser but some think it is.

 

[gadget73]

Re: Weird Gear Oil

Just curious, but is there any reason to use the specific marine gear oil instead of conventional 80w90 gear oil that I can get at any auto parts store?

 

[bigskiohio]

Re: Weird Gear Oil

i do it because my merc dealer told me it is what he runs and trusts and that it tolerates water better then others.

 

[davemoore]

Re: Weird Gear Oil

UPDATE

Ok, after being out all day yesterday, I took another sample today of the gear oil, and put it on a white paper, and took a picture of it. I brightened the photo a lot so you could see the specks really good... (See below)

Upon further examination, it looks like the black specks might actually be some kind of rubber... but the question is, what rubber could it be? Is this oil disintegrating some seal or something? What the heck is it?

The largest speck I've seen so far is in the top left corner of the photo, and when I took a flat screwdriver to it, it does break up like some kind of powder.

Should I drain it out and refill with regular gear oil???

I'm at a loss...

 

[1980Galaxy]

Re: Weird Gear Oil

from the pic it looks like the old oil in there with the new (in my opinion). when you drain the oil, there will still be a little bit still in the outdrive and if it doesn't mix with that new synthetic oil, then thats what i would imagine it would look like, right?

 

[davemoore]

Re: Weird Gear Oil

from the pic it looks like the old oil in there with the new (in my opinion). when you drain the oil, there will still be a little bit still in the outdrive and if it doesn't mix with that new synthetic oil, then thats what i would imagine it would look like, right?

That's what I thought too, until I put it on the paper today and rubbed a chunk of it with a screwdriver blade.

I'm now thinking that maybe when I fried my impeller, some of a seal may have broken up and gone into the gear oil, and that's what I'm seeing now... I think I will change the gear oil again, and let it drain for like 2 hours, and then refill it again and see what we get...

I think I may go back to traditional oil too...

 

[fabrimacator21]

Re: Weird Gear Oil

I don't know exactly what the impeller looks like but I know it's rubber. Could that possibly be wear from the impeller?

 

[davemoore]

Re: Weird Gear Oil

Yes - I suppose it's possible that the fragments of impeller were able to pass through a seal, but I'm still not sure I understand how they would get into the gear lube.

I thought the areas in the lower and upper units where the gear lube is were sealed... but I'm just not sure.

I'll be interested to hear what Don S. says on this...

Good call though...

 

[bruceb58]

Re: Weird Gear Oil

No way that you have pieces of impeller in your gear oil.

 

[myoldboat2]

Re: Weird Gear Oil

No way that you have pieces of impeller in your gear oil.

agreed. the impeller is in the cooling water path. you would've had a lot of water in your gear oil!

if it were mine, i'd drain that batch and refill with the gear oil i decided on--either merc hi performance or a synthetic--and then stick with that choice. for me, i'd stay with merc hi performance outdrive gear lube+.

 

[davemoore]

Re: Weird Gear Oil

No way that you have pieces of impeller in your gear oil.

Ok... well, I wonder what the heck it is then...