Author Topic: C9 400 HP Excess oil from breather tube  (Read 503 times)

Bryan Beamon

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C9 400 HP Excess oil from breather tube
« on: June 19, 2024, 01:03:23 AM »
After a 160 mile drive today found oil on ground from the breather tube and minor amount on the tow shield. Checked oil level and it was 1/4 inch over filled but had been that  level since last oil change at 1000 miles ago. Coolant level was full and hydrolic  fluid level full. Any ideas as why the oil leak from the breather tube was excessive?
C & Bryan Beamon
2006  to present
2007 Contessa 42ft Cat C-9 400hp
1996 to 2006 97 Beaver Patriot Camden

Frank Bergamo

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Re: C9 400 HP Excess oil from breather tube
« Reply #1 on: June 19, 2024, 03:36:14 AM »
Overfilled crankcase will push excess out breather tube. Next oil change, put the exact amount of oil that the spec calls for, then check dip stick and mark the level with a file to calibrate dip stick. It is common for the dipstick to not be accurate, as the dipstick is installed by the coach manufacturer, not the engine manufacturer. Hope this helps.
Frank & Paulette Bergamo
2019-       : 2007 Marquis Topaz IV  C-15 600 HP Allison 4000
2014-2019: 2002 Marquis Emerald C-12 505 HP Allison 4000
2004-2014: 1986 Executive Diplomat 3208 250 HP Allison MT-643
Grand Junction, CO.

Bryan Beamon

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Re: C9 400 HP Excess oil from breather tube
« Reply #2 on: June 19, 2024, 04:26:45 AM »
Frank, appreciate the response but this amount of oil is very unusual as I have recalibrate our dip stick 17 years ago and have always added 34 quarts of oil at all oil changes. Also we have driven 1000 miles on the last oil change with no oil coming from the breather tube.Is there any other circumstances that could cause this condition?
C & Bryan Beamon
2006  to present
2007 Contessa 42ft Cat C-9 400hp
1996 to 2006 97 Beaver Patriot Camden

Eric Maclean

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Re: C9 400 HP Excess oil from breather tube
« Reply #3 on: June 19, 2024, 01:57:45 PM »
Excessive oil from the breather or draft tube is indicative of excessive blow by caused by bad piston rings ( worn out or stuck )
An engine that has seen too much dust or dirt will exhibit excessive blow by this condition is usually caused by an air filter system that allows dirt and dust to pass into the engine ( commonly referred to as dusting an engine ) .check for bad or incorrect or air filter or hole in the air filter hoses leading to the engine intake.

But before getting too carried away the first thing to do is as was stated earlier check your oil level as too much oil can also be the cause of oil dumping at the breather tube. From the little resource I've done it appears the C9. Has an oil capacity of 31.7 quarts not 34 if the engine is over filled the excess oil with be picked up by the crank shaft and flong up into the engine ( a phenomenon known as windage ) this causes oil to atomize and carried to the crankcase breather which is overwhelmed by the amount of extra oil and ends up passing it through the breather instead of scavenging it.

You need to make sure you are running the proper amount of oil.

The other thing you might want to do is service or replace  the crankcase breather assembly as it's job is to allow excess crankcase pressure to vent while at the same time it is scavenging oil from that air it is letting escape if the breather is very dirty its ability to scavenge the transient oil is diminished and oil will pass through it and out the draft tube.

Here is a video of the replacement

https://youtu.be/xUY45wGWb-g?si=WStcrrwBy4vEIcLN

Hope this helps
Eric
1997 Patriot Yorktown
3126-B
2009 Chevy HHR
Roadmaster falcon tow bar
Demco Air Force one tow brake.

Eric Maclean

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Re: C9 400 HP Excess oil from breather tube
« Reply #4 on: June 19, 2024, 02:06:27 PM »
Bryan
Here is an earlier thread/ post on the issue that may be of more help

https://beaveramb.org/forum/index.php?topic=10680.0

Hope this helps
Eric
1997 Patriot Yorktown
3126-B
2009 Chevy HHR
Roadmaster falcon tow bar
Demco Air Force one tow brake.

Bryan Beamon

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Re: C9 400 HP Excess oil from breather tube
« Reply #5 on: June 19, 2024, 03:32:43 PM »
Thanks Eric, I saw that video on the crankcase assembly and was hoping that could be the cause. I will pursue changing the assembly and repost results.
C & Bryan Beamon
2006  to present
2007 Contessa 42ft Cat C-9 400hp
1996 to 2006 97 Beaver Patriot Camden