Oil Leakage. How Much of an Issue?

[A_Sails_Pace]

.. I know that may sound like a bit of a ridiculous question, because of course oil leaking is an issue. Though I guess what I am asking is would you deem it normal for some oil to leak and gather over a period of time? Today I noticed a small puddle of oil under the engine block (approximately 50ml or so). Admittedly its the first time I have checked since we came out of the water at the beginning of January (still in the yard now).

It's a 1981 Bukh 20hp and it's in pretty good nick. So I was just wondering if it is common place for some oil to gather, and because I haven't checked it for a while, perhaps its built up?

Advice/thoughts appreciated as always.

Regards,

A.S.P

 

[rotrax]

Clean the area thoroughly and inspect likely areas of leakage. Behind the flywheel, the oil filter and the sump gasket.

See if it comes back, and if possible, where it is coming from.

I have a Bukh DV20 and have taken it completely in pieces. I re-used or re-made most gaskets, only using a new head gasket.

It has no oil leaks, so I cant advise further from experience.

 

[coopec]

I can't advise so listen to the experts on the forum.

For what it is worth I have always believed there is no such thing as a 100% effective seal.

The Top 5 Things Mechanical Seal Users Need to Know

 

[Babylon]

It could be the front seal..?

My boat originally had a 1982 Bukh 20 in it. About ten or so years ago it was losing oil on a Channel crossing and then back, nothing excessive but needed regular topping up. A crook of a marine engineer in Southampton who was the local Bukh dealer at the time (now hopefully in a care home with an evil torturer for a carer) had a look at it, fiddled everywhere, then said to just keep an eye on it. The prick knew exactly what the problem was - i.e. the front seal which he could have replaced in a trice - but he was hoping I'd wreck my engine so he could get the re-build job or stuff a brand new Bukh at me. Shortly afterwards I set off for the West Country single-handed. Crossing Lyme bay into the usual southwesterly I had to motor-sail for eight hours through a bouncy sea. By the time I got to Brixham the bilge was full of oil. That night and the whole of the next day the boat, tied up on the yacht club pontoon mid-harbour outside the protected inner harbour, pitched and rolled viciously as the wind had moved into a NNW gale. By the time things settled down the entire engine bay was drowned with oil, which had also got behind the ply sides to the unpainted surfaces and saturated the wood, and it had also flooded forward under the built-in chart-table/battery compartment/quarter-berth on one side, and under the galley cabinetwork on the other side, saturating that lot of bare wood, also running aft and coating and wrecking my flexible water tanks, etc. Sleeping aboard for the next few days made me very sick indeed (I now hate hydrocarbon fumes!) so I found a delivery skipper and his mate to sail the boat back non-stop to Southampton while I took the train home. Also, it was obviously the front seal according to the Brixham engineer who had a look at it there. Once the boat was hauled out and the old Bukh removed and sold, it took me two weeks of solid work in tight spine and limb-stressing conditions, with the help of industrial oil-industry cleaning agents ordered from Aberdeen, to finally clear the last of the poison. I then re-painted with bilge paint and fitted a lovely new Beta 25 etc.

Apologies for the long story... but if you've got an oil leak then don't ignore it, find out exactly where it is and deal with it now.

 

[ghostlymoron]

It could be the front seal..?

My boat originally had a 1982 Bukh 20 in it. About ten or so years ago it was losing oil on a Channel crossing and then back, nothing excessive but needed regular topping up. A crook of a marine engineer in Southampton who was the local Bukh dealer at the time (now hopefully in a care home with an evil torturer for a carer) had a look at it, fiddled everywhere, then said to just keep an eye on it. The prick knew exactly what the problem was - i.e. the front seal which he could have replaced in a trice - but he was hoping I'd wreck my engine so he could get the re-build job or stuff a brand new Bukh at me. Shortly afterwards I set off for the West Country single-handed. Crossing Lyme bay into the usual southwesterly I had to motor-sail for eight hours through a bouncy sea. By the time I got to Brixham the bilge was full of oil. That night and the whole of the next day the boat, tied up on the yacht club pontoon mid-harbour outside the protected inner harbour, pitched and rolled viciously as the wind had moved into a NNW gale. By the time things settled down the entire engine bay was drowned with oil, which had also got behind the ply sides to the unpainted surfaces and saturated the wood, and it had also flooded forward under the built-in chart-table/battery compartment/quarter-berth on one side, and under the galley cabinetwork on the other side, saturating that lot of bare wood, also running aft and coating and wrecking my flexible water tanks, etc. Sleeping aboard for the next few days made me very sick indeed (I now hate hydrocarbon fumes!) so I found a delivery skipper and his mate to sail the boat back non-stop to Southampton while I took the train home. Also, it was obviously the front seal according to the Brixham engineer who had a look at it there. Once the boat was hauled out and the old Bukh removed and sold, it took me two weeks of solid work in tight spine and limb-stressing conditions, with the help of industrial oil-industry cleaning agents ordered from Aberdeen, to finally clear the last of the poison. I then re-painted with bilge paint and fitted a lovely new Beta 25 etc.

Apologies for the long story... but if you've got an oil leak then don't ignore it, find out exactly where it is and deal with it now.

I agree absolutely. Oil leaks don't get better on their own and will only get worse. I'd try the front seal first by the sounds of it but read up on your engine and put other potential leaks right while your at it. I understand that Bukhs are robust engines so worth spending some time on it. If you don't have the skills/time get a good mechanic to do it.

 

[Stemar]

My aged VP2003 never leaked a drop of oil, so I certainly wouldn't say leaks are inevitable.

Do get the oil out of the bilges. Quite apart from pollution issues, you will quickly develop that MAB stench that is all-pervading, soaks into the GRP and is very hard to get rid of without the right stuff. I used Bioclean because I had a bad case but, if you get to it early, you can get similar stuff from pet shops that has bacteria in it that eat organic stuff including oil.

 

[Daydream believer]

My Volvo had a small leak. Not a lot but just enough to make the void under the engine messy. I now place an oil absorbent cloth, (cut to size) from Screwfix, under the engine. I never really had to top up the oil but noticed that at the end of the season the leak was always a little less.
One year I was short of oil so I only filled to a level where it was 6mm below the full mark. - No oil leak
It seems that if I keep the level down a bit it does not leak. No idea why. I have watched it carefully & there is always enough oil above the "low" mark. It may have something to do with running the engine while motor sailing & the engine tilted. I do not know.

 

[Babylon]

I can't remember the name of the oil industry cleaning product I used, but a key ingredient was orange juice!

 

[PilotWolf]

We had an immaculately clean bilges so any oil or fluid was an issue. I had a great engineer though so was kind of privileged - if I saw any oil or other fluids in the bilge I was going to be riding his butt and he knew I would. He was/is great engineer but owner wanted 'boat' run like a ship so I did daily (usually) rounds to check up on things. BUT I have also cleaned heads and made beds.

I guess its what you think is acceptable. I worked with a guy who's car leaked so much oil he boasted he never had to change it but just to top it up!i I think it was a Polo but remember it being red, the (ambulance) mechanics t-cut 1/2 of it once after he pi$$ed them off, His wife was even more upset having to park it at the BR (those days!) station.

W.

 

[James_Calvert]

Possible candidates...

Worn front oil seal. Easily accessible to change, just need to remove flywheel.

Worn rear seal. Need to separate engine from gearbox to access.

Loose oil filter. Easy to tighten up a bit by hand, no tool required.

Rocker cover gasket. This might have got misaligned on replacement after adjusting tappets. More obviously, the rocker box can also leak oil around the filler cap and the holding down studs if the washers are a bit knackered.

Water pump oil seal. Never had that leak on mine, I think it's usually the seal on the water side that goes first.

Leaking sump plug, if it had been removed for an oil change. Might simply need tightening, but don't automatically assume a drip forming there means it's leaking, more likely to be an accumulation run down from a leak elsewhere.

Best of luck.

 

[coopec]

What are the main causes of diesel engine oil leaks?

 

[James_Calvert]

What are the main causes of diesel engine oil leaks?

Have you read this?

What's meant by the "oil gasket"?

Other not useful ideas there are a missing filler cap and a sump cover damaged from driving over rough ground!

 

[A_Sails_Pace]

Thank you very much for all of the really useful advice, and links. I have started the process of elimination and am looking through a few things. Planning on heading back up to the boat today to see if any has leaked in the last 24hrs so I can get an idea of the rate at which it's leaking.

Thanks again, I have noted much of the detail in the comments above.

 

[PilotWolf]

Have you read this?

What's meant by the "oil gasket"?

Other not useful ideas there are a missing filler cap and a sump cover damaged from driving over rough ground!

Obviously not a boat but I did forget to put filler cap on once and mess was crazy.

W.

 

[PilotWolf]

An alternative view?

W.

 

[Stemar]

Obviously not a boat but I did forget to put filler cap on once and mess was crazy.

W.

I forgot to tighten down the rocker cover on my first car. No obvious signs until I got on the A1 and speeded up. The car suddenly filled with smoke, so I dived into a layby and we bailed out. The passing Plod was very curious about the incident, thinking it was because we'd seem him. He became a little more sympathetic when he saw the oil all over the engine.

 

[Spirit (of Glenans)]

Anyone who has owned a pre-1980s British motorcycle will know all about oil leaks!

 

[neil_s]

Yes - get that tiny puddle under my 1977 Bukh. Usually due to not cleaning up properly after oil filter change. Maybe rocker cover gasket, too. If you have trouble with the front oil seal, oil will be thrown all over your engine box by the flywheel. I got that trouble due to a leaky water pump.

 

[Graham376]

Have you read this?
What's meant by the "oil gasket"?
Other not useful ideas there are a missing filler cap and a sump cover damaged from driving over rough ground!

For boats, change that to - sump rusted through due to long term leak from raw water pump.

 

[Stemar]

For boats, change that to - sump rusted through due to long term leak from raw water pump.

Or, IIRC, an oil pipe on certain Yanmars. Same cause.