Gaining Gearlube???

[Ron in TN]

Mercruiser Alpha One - 20 years old. A few days ago, got alarm and found gearlube reservoir empty. Seems like it had to happen fairly quickly as I check the level frequently. Refilled and level held as usual for several days of use. While checking to make sure it was still holding, I noticed that the level in the reservoir appeared to be increasing. This morning, I got a couple of quick beeps on the alarm and found the reservoir nearly overflowing! Not sure why an alarm for an over-full reservoir but it's the only unusual thing happening. Oil pressure and water temp are both OK per the gauges. Is it possible I have a leaking seal in the lower unit and that water is leaking in after I shutdown? Some clues: 1) Have had a very, very slow gear lube leak forever, "Fixed" numerous times over the years but never goes away completely. 2) Recently hit a large board while accelerating - going maybe 15 mph. No obvious damage. Prop did slip a couple of times but now seems OK even when heavily accelerating for skiing.

Any suggestions how I can be gaining gearlube level appreciated. Thanks, Ron

 

[Searay205]

You may have air in the system and it burping it out. Oil expands when it gets hot so some level fluctuation is normal. I seen many overflow after a refill. Once it lines out it should not have to add any oil between 100 hr flushes

 

[alldodge]

The lube bottle has a one-way check valve in the top cap. The cap allows air in but not out. Normally as the drive heats up pressure is also increased and the cap keeps the pressure contained. If the valve goes bad then as the pressure increases the lube also fills the lube bottle further and can leak out into the bilge.

In short, you need a new cap

Howdy and :welcome: to iboats

 

[Ron in TN]

Thanks for the very quick replies. As much as I appreciate the explanations, I'm a little skeptical. I wouldn't think that gearlube would expand with temperature. Now if there was some air in the system, that would explain the increased volume. I did see some comments from a forum member "wingnut" who spoke about "shear." as the culprit but it seems if the problem was shear, the level would fluctuate. First lower while hot and then higher if water got in.

Regardless, based on the replies kindly provided, our current very hot weather and that my outdrive sits in the sun in the afternoon (out of the water usually), I would assume that the level would be down early in the morning? I will check and post. Again, thanks for the quick replies. Much appreciated.

 

[Ron in TN]

Level down very, very slightly this morning. Probably would not even have noticed the change if not looking very carefully.

Checked the reservoir cap valve - seems to be working as intended. Wondered if a loose or cross-threaded cap might have caused the problem? Made sure the cap was on properly.

Put the boat in the water - it's on a lift - and went skiing as usual. Checked immediately after skiing - no change.

Checked again on returning to the dock - no change.

I will continue to monitor level very closely and post if anything changes.

One more time....thanks for the suggestions.

Ron