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Author Topic: oil leak  (Read 1236 times)
ol713
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« on: September 18, 2006, 08:08:05 PM »


HI all;
      Came back from a weekend outing a couple of weeks ago and noticed a real bad oil leak.
      What I need is some idea of what to look for.  The leak seems to be on the forward side
      of the blower.  I could see some puddeling in that area.  The oil appears to run down the
      forward end of the r/h head and drip on the starter motor.  Would like some idea of what to
      look for, an external feed line or do I have a blown seal? 
      Motor is an 8V71 in an MC-7.
     
      Thanks,  Merle.
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NJT5047
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« Reply #1 on: September 18, 2006, 08:24:36 PM »

Clean the engine and see where, exactly, the oil is leaking from.  Once that's known, diagnosis won't  be far behind!
But you gotta get the engine clean and see what gets wet.
Are you shure it's an oil leak and not a fuell leak?  In the meantime keep your oil level low....just above the add mark.
Cheers, JR
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JR Lynch , Charlotte, NC
87 MC9, 6V92TA DDEC, HT748R ATEC

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gumpy
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« Reply #2 on: September 20, 2006, 04:52:12 AM »

JR,

I agree with what you said regarding cleaning the engine to help locate the leak, but I don't understand your reasoning for keeping the oil level low. What am I missing?

The leak is described as being up around the blower, which is way above the sump level. This means the leak can only be occurring from pressurized oil. I can't imagine how running the engine with a low oil level could possibly have any effect on the leak (at least not until the level gets so low that the pressure drops, and then it really don't matter  Wink .  Seems to me this only puts your engine at a higher risk of running out of oil and causing major damage, especially considering there's a bad leak already dumping oil OUTSIDE the engine.

Can you expound on your statement and give us your reasoning. I just don't see it. Maybe I'm just missing the logic here.

If anything, I'd recommend checking the level more frequently, and make sure it full at all times.

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Craig Shepard
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NJT5047
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« Reply #3 on: September 20, 2006, 01:03:43 PM »

As long as the oil is above the "add" mark, it won't starve for oil.  I've never been privvy to the engineering concept of not running a 2 stroke DD at the full mark.   But my best guess is that windage is stirring up the oil or perhaps just keeping more vaporized oil circulating in the crankcase, blower, and other spaces.
Running a well used Detroit between half and add mark was a common habit of truckers when 2 strokes were common in OTR use.   
I did it in my 435, and after puking oil all over the bus after filling it completely with oil once ...ran the oil at 1/2 mark (but above the add mark) for two years in the bus. It helped, as did keeping the speed below 65 MPH.  My worse leak was the rear main.  Finally replaced the oil seal and wear ring and the oil leaks are pretty much contained.  I still don't fill it more than 1/2 to 3/4 mark.  And don't add until it gets to the add mark.
One thing to be considered, is that the correct dipstick is in the engine.   Any error there could be catastrophic.
If an engine doesn't leak, and some don't, or burn oil excessively, keeping the oil at the full mark is desirable.  Cools the engine.   But if it's going to loose a gallon every 500 miles, running the oil at less than the full mark, just as long as it doesn't run below the add mark, the engine won't care.   
Repairing the leaks is always a best scenario, but, that can be rather expensive.  Probably require a major overhaul. 
If I had a leaker, I'd also be sure that the alarmastats are functioning.   
Another thing with checking the oil is don't check it unless you have time for the oil level to drip down.  That's another discussion.
JR

JR
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JR Lynch , Charlotte, NC
87 MC9, 6V92TA DDEC, HT748R ATEC

"Every government interference in the economy consists of giving an unearned benefit, extorted by force, to some men at the expense of others.”

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Busted Knuckle
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« Reply #4 on: September 21, 2006, 12:29:15 AM »

Merle,

Just a wild guess as you mention the leak possibly being at the front of the blower, there is a small oil tube that goes from the blower to the Altenator that is known for cracking an leaking! I'd check here first! I've seen many of 'm leaking! BK Grin
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eagle10
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« Reply #5 on: September 21, 2006, 07:12:50 AM »

I just fixed an oil leak that it  took me awhile to find. I could see oil all over the right passenger side of the engine area so I cleaned it and hunted for it. It turned out the leak was on the left driver's side. It was the oil turbo line assembly that had  a small hole in the steel line. Keep hunting for the source as some are difficult to find and even more difficult to repair. This is on my Eagle 10 6v92T.
Good hunting!
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TomC
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« Reply #6 on: September 22, 2006, 08:00:57 AM »

I know at least on my bus with a V drive 8V-71N and a Luberfiner bypass filter, the oil level has to be down 5 gal before the oil light comes on.  I know this since the very first mechanic that worked on it put in only 5 gal and took it for a ride (with me in it) and the oil buzzer was buzzing at idle, but went off when revved.  When we got back he put in another 5 gal and it was alright.  Since then I have had the engine overhauled and all bearings were alright.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
Sammy
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« Reply #7 on: September 22, 2006, 01:28:19 PM »

I agree with Knuckle - check the oil feed tube from the blower drive housing to the blower.
It has a small seal ring inside it that can be replaced, but I recommend to replace the whole fitting assy.
I have recently seen a rotted metal blower end plate(for the first time)that was causing an oil leak.
Check the rubber seal between the blower end plate and the blower drive too.  Cool
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ol713
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« Reply #8 on: September 22, 2006, 08:44:15 PM »

Merle,

Just a wild guess as you mention the leak possibly being at the front of the blower, there is a small oil tube that goes from the blower to the Altenator that is known for cracking an leaking! I'd check here first! I've seen many of 'm leaking! BK Grin

Thanks,   That is what I was hoping to hear.  My Altenator is belt driven,  but it is still worth a look.
                                Thanks,  Merle
« Last Edit: September 23, 2006, 08:09:10 AM by DrivingMissLazy » Logged
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