What Is an Acceptable Oil Leak

[Simister]

I have a Volvo md22 engine with 1800 hours.

It has a minor oil leak coming from the rear seal. It has only about 6 drips of oil per day. It only drips when the engine is running.

I am not sure if I should go ahead and get this seal replaced or could I cause more problems changing the seal and find It then leaking somewhere else.

Is sort of oil leak common on diesel engines?

John

[delmarrey]

Oil leaks are common on OLD motors due to the hardening of the seals. Placing absorbent pads under the motor will keep the bilge clean. The problem is, if it's the rear main seal, the oil is leaking onto the flex plate (flywheel) and slinging it all over inside the bell housing. On a car w/standard trany that would be trouble by getting the clutch oily. But on a boat it MAY BE creating an oil mist in the motor compartment and making a big mess depending on the design of the bell housing.

And are you sure it's the rear main seal. Sometimes the valve cover gasket leaks allowing oil to run down the back of the motor. Unless the motor is clean it's hard to trace an oil leak.

Not knowing your mechanical skills or finances it's a hard call. But if it were mine I'd replace the seal. The smell of hot oil is not one of my favorites.

[Simister]

The motor is very clean. It appears to be coming from one of the bolts at the bottom of the bell housing. It has been leaking for about 5 years and has not increased in all that time.
John

[delmarrey]

Originally Posted by Simister

The motor is very clean. It appears to be coming from one of the bolts at the bottom of the bell housing. It has been leaking for about 5 years and has not increased in all that time.
John

Well then, I think an absorbent pad would be in order!

[sww914]

I'd leave it alone for now.
Let me qualify that by stating that I'm a mechanic but I've specialized in older air-cooled cars that typically leak oil. I've grown used to a little bit of oil leaking in a spot or two so what's acceptable to me might drive another person off of a cliff.
I guess it's your cliff.
Our rule-of-thumb was that if a large pizza box on the garage floor was saturated in a week it was time to fix it. That doesn't apply directly but you get the idea.
Exceptions would be any perfect car or most race cars. Not acceptable on either. If your boat's engine room is perfect then you should fix it.

[Simister]

Thanks for the info. I will leave it as is. It is not causing any problem and is very small.

I figure that if I keep fixing these very minor things I may be chasing my tail forever. If my bilge wasn't as clean as it is I would never know I had an oil leak.

John

[MarkSF]

Originally Posted by Simister

Thanks for the info. I will leave it as is. It is not causing any problem and is very small.

I figure that if I keep fixing these very minor things I may be chasing my tail forever. If my bilge wasn't as clean as it is I would never know I had an oil leak.

John

You should still place an absorbent pad under it though. Around here they are free to get and to exchange once saturated.

[Blue Stocking]

My W46 W/beke is affectionately called "the tomcat". Periodically, it marks its territory.

[Simister]

Well said!!

[ATC]

I have a Detroit Diesel - I have oil leaks. It's been said Detroits bleed oil....

Put the absorbent pads for oil under the bell housing and manage the situation.

[Florida Mike]

Even in the old 671, can be made to stop dripping oil. We had one in an old fire truck. They changed the valve cover and put some kind of collection boxes on the some dirt tubes that came out on the blower. I forget what they were called but it worked. Just my two cents, Mike.

[Mark Zarley]

Do not know anything about your motor, but if you have a drain plug in the bottom of your bellhousing I would remove it and leave it out. This would let that small amount of oil drain out and not accumulate.

[Simister]

Thanks for that. Yes, I intended doing that on the next oil change.

[Chief Engineer]

Put small cans under the pipes that lead off from the air box....that will colect the mist/drips

[Simister]

Thanks for that.
I have tried to capture the mist drips and I still think that could be the source of the oil. The actual drip show up right at the bottom of the bellhousing. When I am motoring along at 2000 rpm there will be no sign of a oil for many hours. It seems that when I stop the engine that the oil appears at the bottom of the Bellhousing. I have tried to see if it migrating from somewhere else but eveything else looks quite dry.