Transmission oil disappearu

I have a problem with my Mercruiser V8 5.7 litre inboard engine. The gear lube in the reservoir is leaking out and ends up underneath the engine in the engine bay, after using the boat and switching it off. I have had it at a boat repair shop five times already and they say that they filled the oil correctly and did a pressure test but they cannot find out where it is leaking.
Does anybody have any advice please?
Herman Barnardt. South Africa

1) Find another repair shop.

2) Is this an inboard with a transmission or an inboard/outboard? ( outboard style drive hanging off the transom)

Hi Capt Bob.

Thank you for the reply.

It is a stern drive Alpha I Gen 2 Mercruiser. The drive is outside the boat hanging from the transom.

If I take it to another shop, I will have to pay again.

I will really appreciate your advice.

Herman Barnardt.

If you can determine if the black rubber hose from the reservoir is leaking or not and if it is not then the most likely issue is the upper carrier seal in the upper half of the out drive. when this seal goes bad gear oil will leak out into the u joint bellows and eventually leak into the bilge. You may have to pay to have it fixed. If so make sure they check the cap bearing as it most likely is bad now that the oil level has been low or nonexistent in the upper.

They should be pressure checking the drive (empty of oil) at 15 to 17 psi.

See link below and it is Item 19 the seal or item 18 the carrier plus seal, as it has the seal already installed.

http://www.marineengine.com/parts/m...l100040-up/driveshaft-housing-and-drive-gears

Upper cap bearing is item 2

http://www.marineengine.com/parts/m...0l100040-up/driveshaft-housing-and-driveshaft

What "Kghost" said, plus... if after 5 trys they kept doing the same thing and didn't look into the bellows to check, you still need to find another shop. I would not have any confidence in this shop to do the correct fix even after you point them in the right direction. IMHO, upon finding that there was no pressure leak, the bellows should have been checked before starting the engine again, the first time you had it there...

Dear Kghost and Sandkicker;

Thank you very much for your replies.

I am told that they did do a pressure test and that they could not find a leak in the hose. I will forward your advice to them and give them one last opportunity to repair my boat, whereafter I will take it to another shop at their costs.

Does it make any sense that the oil only drains out of the reservoir after I stopped using the boat and while it is lying still in the water?

Your assistance and advice are appreciated very much.

Regards.

Herman Barnardt.

563948]If you can determine if the black rubber hose from the reservoir is leaking or not and if it is not then the most likely issue is the upper carrier seal in the upper half of the out drive. when this seal goes bad gear oil will leak out into the u joint bellows and eventually leak into the bilge. You may have to pay to have it fixed. If so make sure they check the cap bearing as it most likely is bad now that the oil level has been low or nonexistent in the upper.

They should be pressure checking the drive (empty of oil) at 15 to 17 psi.

See link below and it is Item 19 the seal or item 18 the carrier plus seal, as it has the seal already installed.

http://www.marineengine.com/parts/m...l100040-up/driveshaft-housing-and-drive-gears

Upper cap bearing is item 2

http://www.marineengine.com/parts/m...0l100040-up/driveshaft-housing-and-driveshaft[/QUOTE]

[email protected] said:

The gear lube in the reservoir is leaking out and ends up underneath the engine in the engine bay, after using the boat and switching it off.

Click to expand...

[email protected] said:

Does it make any sense that the oil only drains out of the reservoir after I stopped using the boat and while it is lying still in the water?

Click to expand...

When you turn the engine off, do you actually see the oil leaking/flowing out the reservoir? Or do you just happen to shut the engine off, lift the hatch cover and notice the oil in the bilge area?... Or see it dripping down? If yes to seeing/knowing it's leaking, is it coming from the top side or the bottom side of the reservoir cap?

Either way, if it's leaking from the Reservoir cap area, then the reservoir cap seal and/or vent could have became compromised during past services and installing a new reservoir cap from Mercruiser is definitely worth a try and could possibly just solve your whole issue.....

You're looking for Mercruiser part number 36-806727 1 = Reservoir Cap as seen in item number 23 in the following link, http://www.marineengine.com/parts/m...8-and-up/0l100040-up/oil-reservoir-components

Dear Boat Tech.

Thank you very much for your reply.

When I have used the boat and moored it, I check and see that the oil level in the reservoir is between the high and low lines, but when I come back after an hour or so the reservoir is empty. There is already oil in the bay area from before so I do not know when it leaked out.

The Boat repair shop said they did a pressure test and that the rubber hose is not leaking. I can also not see any visible oil leaking from the portion the hose that is visible or the reservoir itself or the cap.

I have also replaced the cap last week.

Please advise me.

boat_tech said:

When you turn the engine off, do you actually see the oil leaking/flowing out the reservoir? Or do you just happen to shut the engine off, lift the hatch cover and notice the oil in the bilge area?... Or see it dripping down? If yes to seeing/knowing it's leaking, is it coming from the top side or the bottom side of the reservoir cap?

Either way, if it's leaking from the Reservoir cap area, then the reservoir cap seal and/or vent could have became compromised during past services and installing a new reservoir cap from Mercruiser is definitely worth a try and could possibly just solve your whole issue.....

You're looking for Mercruiser part number 36-806727 1 = Reservoir Cap as seen in item number 23 in the following link, http://www.marineengine.com/parts/m...8-and-up/0l100040-up/oil-reservoir-components

Click to expand...

If you have Gear oil in the bilge and it is not leaking from the cap or reservoir, It is either leaking through the drive shaft seal on the drive or the rubber line/quick connector on the transom assembly.

You cannot pressure test a drive when it is full of oil.

The drive has to be removed and drained then pressure tested.

When the drive is removed and there is gear oil in the bellows it pretty much narrows down what is leaking.

in Short, find a better shop and pay again.

re: "Does it make any sense that the oil only drains out of the reservoir after I stopped using the boat and while it is lying still in the water?"

Drive sits in water, gets to same temp as water.
Run engine, drive warms up, pressure increases
Oil leaves drive
Boat sits in cool water, pressure drops, partial vacuum develops within drive and,
Sucks oil from Reservoir and refills drive...

The reason that both Chris and I recommend a different shop is twofold.
1) Initial error in diagnosis and repeated same tests indicates they are not familiar with MERC drives. This is NOT an uncommon problem.
2) The repair, if it is the seal on the drive shaft, requires some amount of expertise, and given their past performance, neither Chris nor I have ANY
faith in their having the ability to perform the required repair correctly even after you tell them what to fix.

Caveat Emptor..