New boater

atomb

Petty Officer 1st Class
Joined
May 1, 2009
Messages
335
Hey Im a new boater my first season was last year and have done some knucle brained things since starting this great new hobby. I have asked a few questions before and need help on a theory how i hurt my engine last season. thge boat is a 96 mercruiser 3.0lx anyhow. Last run of the season found oil in the bilge that spewed from the gaskets of the oil pan on the port and starboard side. I was running without the dipstick tube in (yes im a knuclehead but what is done is done) Anyhow i was running not wide open but close when this oil blowout occurred. Is it possible that a suction occurred of air at the oil dipstick hole -and all that pressure built up in the crankcase causing the gasket to collapse and spurt the oil out the sides. I have ripped this engine apart and have no signs of mechanical failure anywhere.
 

mkast

Lieutenant Commander
Joined
Nov 6, 2002
Messages
1,934
Re: New boater

Is it possible that a suction occurred of air at the oil dipstick hole

From what?
There is usually crankcase pressure, caused by combustion pressure getting past the piston rings, hence, the Positive Crankcase Ventilation system.
 

atomb

Petty Officer 1st Class
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May 1, 2009
Messages
335
Re: New boater

Is it possible that PCV system got overloaded ,backed up a bit? possibly? maybe blocked?
 

mkast

Lieutenant Commander
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Messages
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Re: New boater

Is it possible that PCV system got overloaded ,backed up a bit? possibly? maybe blocked?

Even if it did, the pressure would escape out the dip stick hole.
 

atomb

Petty Officer 1st Class
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May 1, 2009
Messages
335
Re: New boater

so why would the oil bust out thru the the oil pans gasket? In your opinion-
 

mkast

Lieutenant Commander
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Re: New boater

How loose were the pan bolts?
 

atomb

Petty Officer 1st Class
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May 1, 2009
Messages
335
Re: New boater

When i pulledthe pan off it really seemed like the factory did a good job not super tight but not loose -actually the two leaks were really in between the bolts and the gasket was beautiful when i took it off -and this was de the first time it had seen daylight this pan was original.
 

mkast

Lieutenant Commander
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Nov 6, 2002
Messages
1,934
Re: New boater

If the oil pan was indeed torqued correctly, the mating surfaces (pan and block) are straight edge flat, and the gasket didn't have any material missing or torn, the oil leak is just your imagination.
 

atomb

Petty Officer 1st Class
Joined
May 1, 2009
Messages
335
Re: New boater

well 1 quart of oil in my bilge was not my imagination lol.
 

atomb

Petty Officer 1st Class
Joined
May 1, 2009
Messages
335
Re: New boater

your saying basically the fault here really points to faulty gasket and or poor tension of boltings. Maybe im just looking to hard at this i would have thought that there had to have been some other event that could have caused this.
 

mkast

Lieutenant Commander
Joined
Nov 6, 2002
Messages
1,934
Re: New boater

I don't doubt the oil in the bilge.
I rather believe you missed the oil fill hole and poured the quart into the bilge than believe a mysterious suction built up in the crankcase and blew out the pan gasket.
 

atomb

Petty Officer 1st Class
Joined
May 1, 2009
Messages
335
Re: New boater

nah -yes i am a knucklehead but really im not that far gone. I heard the pressure blow when i was up at speed and i bogged my way home to the dock.
Your funny.:D
 

atomb

Petty Officer 1st Class
Joined
May 1, 2009
Messages
335
Re: New boater

Usually, the term ''blow(s) a gasket'' means the gasket went
bad.

However, and oil pan (or even a rocker cover) gasket can start leaking if
for some reason internal engine pressure gets too high, making the
pressure try to find an exit (the weakest point).
Usually this is a high mileage engine, worn rings, combustion blow by,
crankcase not ventilating properly

I found this on the web and i think im going to use this info as my cause -tell me what you think? thanks for pointing me in a direction.
 

mkast

Lieutenant Commander
Joined
Nov 6, 2002
Messages
1,934
Re: New boater

Usually when a gasket goes bad (apparently didn't get involved in sports as a youth) there will be evidence, such as a torn gasket or missing gasket material.
 

Aviator5

Chief Petty Officer
Joined
Feb 10, 2009
Messages
431
Re: New boater

I totally agree with Mkast, the cause is much simpler than a mysterious pressure buildup.
Have you done any diagnostics on the engine before ripping it apart? Compression check perhaps?
 

atomb

Petty Officer 1st Class
Joined
May 1, 2009
Messages
335
Re: New boater

Thread closed -thanks for all the input.
 

Bondo

Moderator
Staff member
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Apr 17, 2002
Messages
70,468
Re: New boater

Ayuh,... Are you sure it ain't rusted through somewhere,...
Queens is Saltwater....
 
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