Volvo Penta outdrive oil/grease leak

[elmoon]

Have a Volvo Penta AQD21 with a 250D outdrive. The boat is in fresh water.

Left her sitting over the winter. Used her a couple of times this week.

After 1.5 hours cruising yesterday, moored up and noticed tiny patches of oil/grease coming up from around the outdrive for a couple of hours after stopping.

Checked the oil dipstick and it looks clear (not milky) and 3/4 of the way filled on the level markers.

What could it be? A seal gone somewhere in the leg? Or related to this hot weather?

Only other issue to report, the helm (hydraulic steering wheel, Vetus MT30) wasn’t doing anything when I first came back onboard the boat. Topped up the hydraulic steering oil at the steering wheel and it works fine now. Slightly overfilled it as oil came out of the plug when bled through for a bit even when closed. Must have leaked from somewhere, can only see a tiny drop under one end of the hydraulic ram in the engine bay, keeping an eye on it.

Also fouled the prop on some lilipads when coming out of the berth the other day, but soon cleared them and carried on.

Anything related?

I have owned a variety of boats over the last 15 years and am relatively practical but not familiar with outdrives. Would appreciate any advice.

 

[elmoon]

To answer my own question, I don’t believe this issue is connected with the hydraulic steering oil, they’re two separate systems. Most likely it’s a seal, perhaps from the oil drain hole?

 

[Momac]

Could it be grease from the steering or grease applied to the shaft when fitting the prop. If so no issue at all?

 

[elmoon]

Could it be grease from the steering or grease applied to the shaft when fitting the prop. If so no issue at all?

Hi Martyn. It could be, I considered this, but doesn’t explain why it has suddenly appeared. Prop hasn’t recently been greased. Unless it’s to do with the hot weather.

 

[simonfraser]

check the hydraulic level in the OD pump, if that is reducing you'll have your answer
did you leave the 250D down over the winter ?
if not the barnies on the rods damage the seals

 

[elmoon]

check the hydraulic level in the OD pump, if that is reducing you'll have your answer
did you leave the 250D down over the winter ?
if not the barnies on the rods damage the seals

It doesn’t have an electric lift/tip/trim mechanism fitted so not sure there’s a hydraulic pump to check or that it has those rods? Yes left it down over the winter.

 

[simonfraser]

It doesn’t have an electric lift/tip/trim mechanism fitted so not sure there’s a hydraulic pump to check or that it has those rods? Yes left it down over the winter.

so how do you get the leg to go up / down ??

you presumably checked the engine oil as the outdrive oil can not be checked unless the boat is out of the water ??

 

[elmoon]

so how do you get the leg to go up / down ??

you presumably checked the engine oil as the outdrive oil can not be checked unless the boat is out of the water ??

It doesn’t go up and down, it’s fixed in the down position. Can check the oil with the dipstick on the top of the leg.

 

[simonfraser]

have you got a pic of your 250D outdrive ?
from what i can see on line they all tilt up / down

 

[elmoon]

have you got a pic of your 250D outdrive ?
from what i can see on line they all tilt up / down

Yep, here’s one…

 

[James jameson]

Unless it’s been removed the 250 has a motor and worm gear mounted on the inside of the transom plate, this pushes a mechanical bar down through the transom plate, This in turn pushes on a casting to the port side of the outdrive.
All of this is mechanical no oil is used.
if that’s all been removed it will just be locked in the down position

The steering and drive and engine for that matter are separate systems which share no oil,
it can only be assumed the drive is leaking oil from one of the seals be it prop shaft, gear selector of if the drive bellows are shot main seal. Prop shafts wear grooves in time which result in even new seals letting by.

The only way to be sure is lift and pressure / vacuum test unless it’s obviously dripping out.
I would top it up and keep any eye on it then use it till you can get the boat out of the water.

 

[simonfraser]

wow, k, how old is that leg ?!
anyway, could have a leak from the prop shaft or other seals on the 250D
if the oils are clear you may want to sit it out until lifted for the winter
but keep checking the oils for contamination you can quickly cause damage and expense running it with contaminated oil

 

[elmoon]

Unless it’s been removed the 250 has a motor and worm gear mounted on the inside of the transom plate, this pushes a mechanical bar down through the transom plate, This in turn pushes on a casting to the port side of the outdrive.
All of this is mechanical no oil is used.
if that’s all been removed it will just be locked in the down position

The steering and drive and engine for that matter are separate systems which share no oil,
it can only be assumed the drive is leaking oil from one of the seals be it prop shaft, gear selector of if the drive bellows are shot main seal. Prop shafts wear grooves in time which result in even new seals letting by.

The only way to be sure is lift and pressure / vacuum test unless it’s obviously dripping out.
I would top it up and keep any eye on it then use it till you can get the boat out of the water.

Thanks James, really useful. I will keep a close eye on it for now. If the problem doesn’t reoccur I will wait until winter haul out. If it keeps happening, I found an engineer who can take a look next week, and am in a small yard where she can be lifted with little problem.

I can’t see in my manual where the gear selector seals would be, could you explain more? Also you didn’t mention it but I’m wondering if the oil drain plug has a seal which could also be the culprit.

 

[James jameson]

Thanks James, really useful. I will keep a close eye on it for now. If the problem doesn’t reoccur I will wait until winter haul out. If it keeps happening, I found an engineer who can take a look next week, and am in a small yard where she can be lifted with little problem.

I can’t see in my manual where the gear selector seals would be, could you explain more? Also you didn’t mention it but I’m wondering if the oil drain plug has a seal which could also be the culprit.

On the rear of the drive an angled cover with 2 screws under that is the gear shift mechanism it’s got a set of seals, not something you can do much with in the water though.

usually you get emulsified oil not an actual drop in level.
yes the drain plug has an o ring seal as does the dip stick in the top

Was the oil actually at the correct level to begin with ?
lots of old drives have emulsified oil in them and to be fair usually pretty indestructible in you’re use as I’m guessing by the pic and the added steering plates on the inland’s somewhere and it’s under little stress.
Not good to have water in the oil but loads have and they survive !

 

[elmoon]

On the rear of the drive an angled cover with 2 screws under that is the gear shift mechanism it’s got a set of seals, not something you can do much with in the water though.

usually you get emulsified oil not an actual drop in level.
yes the drain plug has an o ring seal as does the dip stick in the top

Was the oil actually at the correct level to begin with ?
lots of old drives have emulsified oil in them and to be fair usually pretty indestructible in you’re use as I’m guessing by the pic and the added steering plates on the inland’s somewhere and it’s under little stress.
Not good to have water in the oil but loads have and they survive !

Yes, flat inland freshwater. Not usually run for long periods at a time.

Can’t remember what the oil level was last time I checked, will make a point of checking it every time I run it (as I do the main engine oil). But now it’s 3/4 full between the dipstick marks, very clear oil, not black, nor white/emulsified.

Maybe it was too full and this heat made it expand and the weakest point was the drain plug seal. But it has stopped now, and the level still reads 3/4 full.

 

[James jameson]

Although is painfully slow you can top It up through the dipstick hole.

When you say 3/4 that’s on the half flat part at the lower end of the dip stick ? If so that’s fine for a level