what are the consequences of too much oil in an engine

Grt

New member
Joined
14 Nov 2006
Messages
7
Location
Kent
Visit site
The stbd Kad32 on my s28 has always breathed quite heavily leaving a trail of oil under the engine and into the bilge. It usually occurs after a run of a couple of hours.
I’ve just had it serviced including new oil and crank case filter but from the short distance from my berth to the hard it has already spit out oil. The dipstick measures at least a cm above the max mark. Could too much oil cause damage or excess breathing? (I am sure it is from the breather and not a spillage!)
 

Nick_H

Active member
Joined
20 Apr 2004
Messages
7,662
www.ybw-boatsforsale.com
Well there's experts on here who will know much better than me, but i'm sure too much oil will cause high oil pressure, which could certainly force it out of the crankcase breather valve (that's what it's there for after all), so you would see oil in the filter. If the breather doesn't release the pressure, you could blow oil seals which is loadsamoney to fix. I've also been told that if it's very overfilled the engine can start to run on the oil, and then doesn't turn off at the keyswitch.
 

Peanuts

Member
Joined
13 Jun 2005
Messages
711
Location
Poole
Visit site
When I was an apprentice (long time ago) in the Engine Bay I always remember the old guy telling me you can do as much damage over filling an engine with oil as you can under filling it. The marks on the dip stick are there for a reason so suck some oil out to put it at the correct level. Get the person who did the service back to do the job correctly, that's what you paid for!
My main question relates to your statement "The stbd Kad32 on my s28 has always breathed quite heavily leaving a trail of oil under the engine and into the bilge. It usually occurs after a run of a couple of hours" Why? They normally show this oil when the filter is well overdue replacement, how many hours is the engine at? and does it show any other symtoms?
 

sarabande

Well-known member
Joined
6 May 2005
Messages
35,990
Visit site
if you really overfill (not just a cm or so) then internal crankcase pressure can force lube oil along the valve stems and into the cylinders.

At which time the engine is not under control of the diesel fuel injection pump, and can "run away" with masses, I mean masses, of white smoke.

Generally this b*ggers all sorts of bits in the engine :0

It happened to me with an industrial Golf diesel engine which was overfilled, then as we went round a long corner, G force pushed oil into the valve kit, and off she went. Turning off th engine had no effect, so we had to jam the vehicle into gear and stall it on the clutch.

I can't think how one would stall a runaway engine on a boat without running a line round the prop or similar. No, the power would be too great.

FWIW, I don't think a small overfill will hurt, but to be safe use an extractor, and get the level down to norman.
 

pheran

New member
Joined
23 Sep 2002
Messages
12,715
Location
The glorious South
Visit site
[ QUOTE ]
I can't think how one would stall a runaway engine on a boat without running a line round the prop or similar. No, the power would be too great

[/ QUOTE ] Cut off the air supply to the engine. Either cover the intake or ram something into it but if the latter, make sure whatever is used doesn't get sucked right in.
 

John100156

Well-known member
Joined
31 Oct 2007
Messages
2,630
Location
SANT CARLES DE LA RAPITA
Visit site
Or, if you dont want to use an extractor, a simple oil filter change may reduce the level a bit, but definately do something to get the level back down.

I am sure I was told once that over-filling can cause increased crankcase pressure which can cause problems with oil seals! Although I would have thought the breather would have been the path of less resistance? Anyway get it sorted!
 

mainshiptom

Active member
Joined
15 Jul 2002
Messages
3,387
Location
Faversham kent uk
Visit site
I have done it once before a long journey !

An hour into the journey we lost all oil pressure and had to shut down one engine, when we got into harbour the diagnosis was, one oil pressure sender broke off and let all the oil out into the bilge, had to spend a fiver in Halfords to put right and a day lost.

but engine was still good, Perking 6454 Turbo.

Tom
 

dragoon

Well-known member
Joined
13 Oct 2003
Messages
1,744
Location
Gosport
Visit site
I would suck some oil back out, to get the level between the limits.

As suggested by others, high oil level can lead to various scenarios. Another one I've heard of, is the crank running in the oil, and whipping it into a froth which ultimately will lead to lubrication issues.

My Volvo (car) diesel also warns about high oil level leading to catalytic converter damage.

Let us know whether the situation persists after the correct oil level is returned.

Cheers,
Paul
 

rbmitchell

New member
Joined
26 Nov 2008
Messages
4
Visit site
A common problem with too much oil is the crankshaft hitting the surface and foaming the oil. This foam can push out the breather and make a mess of things. It is often best to run the oil level on the low side.
 

Grt

New member
Joined
14 Nov 2006
Messages
7
Location
Kent
Visit site
The engine has 320 hours on the clock and was last serviced 80hours ago including new oil and crankcase filter (which always appears clean – I also swapped with port engine for diagnosis)
Come to think of it, the excess breathing occurred after the last service and it was overfilled then!
As a result of all the valuable posts, I’m going to invest in a Pella and pump some oil out
Probably change servicer as well.
 

Peanuts

Member
Joined
13 Jun 2005
Messages
711
Location
Poole
Visit site
Well it looks like you may have sorted out the problem yourself!
I would invest in a Pella, you will end up using it for other times as well as an oil change, instead of changing your service engineer why not do the work yourself? Plenty of room in a S28, engines easy to work on and there is always advice on here if you need it.

Steve
 

peterandjeanette

Active member
Joined
11 Jun 2001
Messages
1,176
Location
Stratford upon Avon/Sant Carles
Visit site
Further consequences could be an oily/smutty backside.

I always kept the oil topped up to the max mark - even slightly above. At the last service by a well known forumite he recommended keeping the oil to the centre of the limits on the dipstick. Result - no smutty backside.

Obviously, daily oil checks even more essential.
 

Grt

New member
Joined
14 Nov 2006
Messages
7
Location
Kent
Visit site
Good idea Steve. I think I'll do that in the future.
Thanks very much to you and the other forumites for the feedback and advice.
 

Jetta

New member
Joined
24 Feb 2019
Messages
1
Visit site
if you really overfill (not just a cm or so) then internal crankcase pressure can force lube oil along the valve stems and into the cylinders.

At which time the engine is not under control of the diesel fuel injection pump, and can "run away" with masses, I mean masses, of white smoke.

Generally this b*ggers all sorts of bits in the engine :0

It happened to me with an industrial Golf diesel engine which was overfilled, then as we went round a long corner, G force pushed oil into the valve kit, and off she went. Turning off th engine had no effect, so we had to jam the vehicle into gear and stall it on the clutch.

I can't think how one would stall a runaway engine on a boat without running a line round the prop or similar. No, the power would be too great.

FWIW, I don't think a small overfill will hurt, but to be safe use an extractor, and get the level down to norman.

Yes this also happened to me in an 83 vw rabbit. I lowered the oil level and it will not start now. Could you give me any ideas what to look at first to replace?
 

[165042]

...
Joined
25 Nov 2016
Messages
558
Visit site
Well there's experts on here who will know much better than me, but i'm sure too much oil will cause high oil pressure, which could certainly force it out of the crankcase breather valve (that's what it's there for after all), so you would see oil in the filter. If the breather doesn't release the pressure, you could blow oil seals which is loadsamoney to fix. I've also been told that if it's very overfilled the engine can start to run on the oil, and then doesn't turn off at the keyswitch.

The crankcase breather isn't there for releasing excessive oil pressure - it's there for crankcase gases to expel safely.
 

Momac

Well-known member
Joined
7 Feb 2008
Messages
6,778
Location
UK
Visit site
Probably change servicer as well.

I would.
I used to pay for oil change but realised it is easy as a DIY job and the extractor pump paid for itself on the first use.

It's easy to over fill the kad32.
If you pump out the oil with the engine warm, refill with fresh oil up the high mark on the dipstick and leave it overnight the oil level will be above the high mark the next morning as oil held in the engine drains down.
Therefore refill to half way between the marks and check oil level next morning.
Or pump out the oil and leave overnight and pump out again in the morning before refilling. Pumping the cold oil is slower but can be done.
 

sorabain

Member
Joined
3 Sep 2014
Messages
238
Location
London
Visit site
Quite a necro. This thread approaching 10 years old. I wonder how much of a problem this might be in future now that forums seem quite mature and could last lifetimes. It would be quite amusing if in the year 2109 someone necros a thread from 2009 and noone really notices as the date just shows the last 2 digits of the year (although they might be thrilled to learn that so many people are sailing around in 100 year old boats with original engines).
 

TQA

New member
Joined
20 Feb 2005
Messages
6,815
Location
Carribbean currently Grenada
sailingonelephantschild.blogspot.com
1 cm over no problem.

You have to overfill to the point at which the crankshaft dips into the oil. At which point you usually get destroyer hiding quantities of blue smoke. If you carry on running the engine you can get diesel runaway which is very alarming.

Brave people can stop the engine by blocking the air inlet, use a plate or pot lid. DO NOT USE YOUR HAND.
 
Top