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Author Topic: Back of bus always dirty , is this just life with a DD?  (Read 706 times)
neoneddy
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« on: November 03, 2017, 10:17:53 AM »

I've washed it and after 500 miles or so you can run your finger across the back and it will be black and leave a white streak (paint is white).

For this reason I'm planning  on painting the back black for this reason, like attached.  The black wave will wrap around.

Is this just life with a DD 6v92?    I'm letting the oil run down a bit, I used to run it near the F mark, but i read others ran it more near the L (add) mark to keep oil residue down, it seems to be working, it used to be so much worse.



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First time bus owner, long time bus lover  - 1982 MCI MC9 6V92 - Current Status - Livable, still 20-30% more to go.  Video Build Log
lostagain
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« Reply #1 on: November 03, 2017, 11:17:12 AM »

If you are persistent at fixing oil (and all fluid) leaks, it will run clean. If you don't have the check valves on the air box drains, you could install them so it only drips at idle.

I run my 6V92 oil level at the full mark. I like more oil for it's role in cooling the engine. It doesn't use oil beyond what is expected for a 92 series.

JC
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JC
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luvrbus
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« Reply #2 on: November 03, 2017, 11:41:02 AM »

Fix the leaks both exhaust and oil leaks even if you have a drip on the transmission,power steering or differential they will show on the back of your bus.
I am with JC I don't believe in running those engines a gal low,me personally I have never owned a 2 stroke Detroit that would throw the 1st gal of oil out     
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chessie4905
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« Reply #3 on: November 03, 2017, 12:09:21 PM »

They make a Walker air sep for your engine that will take care of oil leaks and the residue. A bit pricey but they work. Developed for marine use to keep engine compartment clean. They will work the same in coach engines. When GM came out with the Olds diesels in late 70's, after several thousand miles, you started getting a faint soot darkening of interior, esp. ceiling from soot coming heater/ac intake. In 1981,along with major engine improvements, they started using what they called crankcase depression regulator. It looked like a tin can with hoses from both valve covers, and a short connector to intake. It was designed to provide a slight vacuum in engine crankcase to remove blowbye and burn the fumes. It worked well as most oil leaks ended and no longer had soot stains in car. They have used this item on all their diesels since. Walker Air Sep is same, only much larger.

http://www.walkerairsep.com
« Last Edit: November 03, 2017, 12:13:08 PM by chessie4905 » Logged

GMC h8h 649#028 (4905)
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luvrbus
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« Reply #4 on: November 03, 2017, 12:14:13 PM »

A 1 inch high air defector on the roof top on the back will stop most of filth on the tale gate on a bus 
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richard5933
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« Reply #5 on: November 03, 2017, 12:24:54 PM »

I've got an 8V71 with only 40k original miles. It leaves residue after only a few miles. Nothing horrible, but it's obvious that the bus isn't clean anymore on the rear. Our Previous coach did the same. I've read it's just part of the joy of DD engines.
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Richard
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« Reply #6 on: November 03, 2017, 12:25:47 PM »

I made a simple catch-jug for the airbox drain tubes  -  with clear tubes going into it I can see just how much oil is coming from each side.   However, I still end up with an oily engine door.   I have some slight drips from the engine and transmission, so I guess they're responsible for the residue on the door.

John
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1990 Crown 2R-40N-552 (the Super II):  6V92TAC / DDEC II / Jake,  HT740.     Hecho en Chino.
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neoneddy
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« Reply #7 on: November 03, 2017, 12:39:05 PM »

Luvrbus : any links or photos to such a deflector?
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First time bus owner, long time bus lover  - 1982 MCI MC9 6V92 - Current Status - Livable, still 20-30% more to go.  Video Build Log
chessie4905
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« Reply #8 on: November 03, 2017, 01:32:32 PM »

That's also why many conversions used a mudflap across the back below bumper. Some use a broom type that works almost as well and can tolerate deflated bags or humped road crossings. Some wine heating issues think these can contribute to it. Replacing original flap in front of rear axle is highly recommended.
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« Reply #9 on: November 03, 2017, 02:14:40 PM »

I fixed all the oil leaks and the oily back end and it only cost me $ 10 k I had the engine rebuilt and never had any oil leaks again

dave
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dave , karen
1990 mci 102c  6v92 ta ht740  kit,living room slide .... sold
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chessie4905
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« Reply #10 on: November 03, 2017, 02:48:58 PM »

That's it. Worn rings...more blow by....then more crankcase pressure resulting in more oil leaks.....resulting on oily film or black film on tailgate.
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GMC h8h 649#028 (4905)
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« Reply #11 on: November 03, 2017, 03:18:56 PM »

The nice thing about a bus, if anything springs a leak, the airflow puts it on the rear, so you'll know.

The bad thing about a bus....

The wise busnut continues to monitor the rear for changes in what, and how much, accumulates.

Early warning system?

happy coaching!
buswarrior
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Dave5Cs
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« Reply #12 on: November 03, 2017, 03:24:29 PM »

And rust prevention on the TOAD
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muldoonman
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« Reply #13 on: November 03, 2017, 04:30:04 PM »

That's it. Worn rings...more blow by....then more crankcase pressure resulting in more oil leaks.....resulting on oily film or black film on tailgate.

Not always rings. Had mine oiling the back of bus and pick up I pulled big time. Turned out Blower Seals. Had it rebuilt early summer and after 1500 hundred miles, no oil out drain tubes/check valves. Engine is clean and hasn't used any oil or dropped any on floor at idle..
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Lin
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« Reply #14 on: November 03, 2017, 04:52:58 PM »

Also, make sure it is oil and not fuel.
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