disappearing drive oil

lrdchaos

Petty Officer 1st Class
Joined
Feb 11, 2008
Messages
265
I just took my boat in to get it winterized, over the course of the season I have had to add aprox. 1\4 qt of gear oil. When I talked to my dealer, which is a very rep. dealer he said that's normal. That mercruisers tend to make oil vanish, that he has talked to merc. and they don't know where it goes either.
Does this sound legit?
 

Gary H NC

Fleet Admiral
Joined
Dec 1, 2005
Messages
8,972
Re: disappearing drive oil

I remember this same topic a year or so back.
If i remember nobody knows where it goes but its normal on the newer mercs...
Good question for Don S.
 

rodboltw

Cadet
Joined
Sep 26, 2008
Messages
15
Re: disappearing drive oil

legit?
yes and no.
but 8 ounces isnt much as long as no water is evident in the gearcase and no oil is evident in the drive bellows when its removed for service at winterization.
its a sealed system so oil cannot simply vanish.
its always possible that it burped some air after the last service. it happens.
 

lrdchaos

Petty Officer 1st Class
Joined
Feb 11, 2008
Messages
265
Re: disappearing drive oil

Thanks guys....just a bump for the morning crowd.
 

Haut Medoc

Supreme Mariner
Joined
Jun 29, 2004
Messages
10,645
Re: disappearing drive oil

Drain the gear oil & pressure test it, (which should be done at layup anyway).......
Examine the color/condition of the lube as well as any signs of lube in the bellows when the drive is off, (more pm) as noted above......
That will be the final answer......;)
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: disappearing drive oil

I have NEVER seen a Mercruiser drive that is properly sealed lose oil. My old 165 never lost oil (I had that for 8 years) and the 1st V6 never lost a drop (had that for 14 years). The new engine is also holding oil nicely. (2 years now)

The most likely place you'll be losing it is the lower shift shaft seal. It's only a single seal and they do weep if not replaced every few years... Pressure/vac test will tell you when it wants to be replaced.

Chris.......
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: disappearing drive oil

A very common place for the early 91-95 Alpha I Gen II drives to loose oil from was the shift shaft bushing that is mounted on the lower unit. Merc came out with a new one with better seals that cured the problem.
PN is 815921A21 and the run around $26 for the whole assembly. They are also made out of a different material.
 

chiefalen

Captain
Joined
May 18, 2008
Messages
3,598
Re: disappearing drive oil

We had my friends lower off yesterday cause it had a little water in the drive oil.

Alpha 2, and it was that seal don.

3 years ago we replaced it when we did the impeller, came in the impeller kit.

It has the spring in it.

When he shifts with the old seal and pressure tested we could hear the sir.

Reach around and jiggle the shift shaft and we knew it was the same seal.

The part # you posted is a direct replacement?

Where can we get it. 26 bucks worth it, costs almost that for the stikin merc oil?

Oh everyone the merc oil is cheaper in Strauss. 9 bucks vs 12 bucks a quart.

Real merc oil the good stuff.
 

chiefalen

Captain
Joined
May 18, 2008
Messages
3,598
Re: disappearing drive oil

Thank you.

Always thought they should come up with a fix for that poorly designed assy.
 

Skinny

Cadet
Joined
Nov 28, 2007
Messages
18
Re: disappearing drive oil

had the same problem, the marina did a pressure test and everything was ok. Were the found the leak was under the oil res tank. It may of leaked 1/4 cup over the season.
 
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