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Author Topic: 8V92 Oil Leak  (Read 4548 times)
Skykingrob
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« on: October 12, 2010, 07:31:07 PM »

I have an 8V92 in my 91 Prevost. Since I got it the drivers side engine compartment door has a vertical line of oil slung onto it by the fan. I have inspected the boston fan drive for leaks around the seals and found none. I then fould the dip stick in the top of the gear box was missing an "o" ring seal, which when replaced did not stop the oil leak. So, I power washed the engine with degreaser until it was totally clean. Then I restarted the engine and watched closely where the leak might be coming from. What I found is there is oil leaking from around where the exhaust pipe attaches to the turbo and when I trace it down the exhaust pipe, there is a right angle bend forward toward the muffler, there where the exhaust pipe attaches to the muffler, there is also oil leaking  around the connection. This connection is directly above the fan gear box and as the engine is running seems to be dripping down on top of the fan gear box shich then slings the oil onto the door. I see there is an oil hose going to the turbo housing. My question is it possible for an oil seal in the turbo to leak oil like this which is then carried along with the exhaust. The exhaust shows very little smoking and there is not the typical "burned oil smell" while the engine is running. Second question is how difficult is it to get the turbo out as I assume it will have to be rebuilt to stop the oil leak if this is really where it is coming from. I would like to make sure this is the problem but do not know any more tests (like separating the exhaust from the turbo housing-would guess it to be very loud) that can be done to verify it any further, ideas??
Thanks
Rob
91 Prevost LeMirage XL
Missouri
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Ace
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« Reply #1 on: October 12, 2010, 08:07:34 PM »

Rob chances are your turbo does NOT need to be removed! There is a small oil line at the back side of the turbo which on the front side of your bus that has been known to leak oil from becoming loose! Mine was and made a heck of a mess. A simple tightening of the fitting cured the leak! Also check your breather tubes coming from the valve covers. If they are broken or loose, also makes a mess! My bet is a loose oil line at the Turbo!

Ace
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Ace Rossi
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Prevost H3-40
luvrbus
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« Reply #2 on: October 12, 2010, 08:36:57 PM »

Pop both exhaust pipes off at y junction and check to see if they are wet sounds like your bus needs to be driven too much idle time not a turbo problem 

good luck
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« Reply #3 on: October 13, 2010, 05:43:51 AM »

You can get a lot of black oily looking fluid from the exhaust that you would think is an oil leak, instead it's some combination of unburnt fuel, soot, oil from idling too much, as Clifford says.

Brian
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« Reply #4 on: October 13, 2010, 05:55:37 AM »

I agree with too much idling possibilty.

After you clean it next time take it out and run it with little or no idling and I bet you will not see oil there.

I too have also seen the fitting Ace described often loose and leaking you can barly reach in and get it from the chassis battery door if you reach real far in.
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« Reply #5 on: October 13, 2010, 10:23:29 AM »

Ok here is what he wrote and what I read!

"What I found is there is oil leaking from around where the exhaust pipe attaches to the turbo and when I trace it down the exhaust pipe, there is a right angle bend forward toward the muffler, there where the exhaust pipe attaches to the muffler, there is also oil leaking around the connection."

The oil starts at the top according to his description NOT at the exhaust. Oil will run DOWNWARD and blow EVERYWHERE when it gets within the path of the fan.

I'm sticking to my assumption that is is the small oil line going to the turbo! I say this because I TOO thought I had a major oil leak and this solved my problem drastically!

If it were from idling too much, I think the guy would admit to this and also he might even see some wetness at the tail pipe or maybe even at the numerous exhaust joints which CAN show exhaust leaks.

Heck he might even have multiple issues he is dealing with!
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Ace Rossi
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Prevost H3-40
luvrbus
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« Reply #6 on: October 13, 2010, 12:24:35 PM »

For hard to find leaks I just use the UV flashlight, dye and the goggles best 50 bucks you can spend.
He made no mention of smoke where the oil was hitting the pipe oil smokes  
I'll stick with the idling who knows he may have a bad seal on on the fuel linkage or clamp broke there or if he has the fitting it maybe loose fwiw not all the turbos on a DD have that fitting some have a plate with the hose and metal tubing made with it.  


good luck
« Last Edit: October 13, 2010, 12:39:44 PM by luvrbus » Logged

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Van
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« Reply #7 on: October 13, 2010, 12:57:09 PM »

Quote

"What I found is there is oil leaking from around where the exhaust pipe attaches to the turbo and when I trace it down the exhaust pipe, there is a right angle bend forward toward the muffler, there where the exhaust pipe attaches to the muffler, there is also oil leaking  around the connection"?
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« Reply #8 on: October 13, 2010, 02:46:53 PM »

Mine did this also. I found that to much idleling and too much diesel in the oil. You may want to change oil if this is the problem. When I did get to get her on the road my neighbors were not happy with the smoke cloud it let out when I stomped on the throttle. I had to get out of town to get all that oil and diesel out of the exhaust system.

John
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John Riddle
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1984 MC9
Skykingrob
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« Reply #9 on: October 13, 2010, 06:19:57 PM »

Guys, thanks for all of the replies as I have read all the answers. I went out to check the oil line going to the turbo, it is tight, there is slight seepage around it but is clearly not the problem.  I do not have a problem with the slobber tubes either, they are new and run well down to the bottom of the engine, happily dripping on the garage floor.

Where the exhaust pipe attaches to the turbo, it is leaking an oily blackish fluid that is dripping down onto the valve cover on the left bank. If you follow the exhaust pipe further, it runs out sideways about a foot then turns 90 degrees forward and downward at 45 degrees passing over the fan gear box. Right above the fan gear box there is a flexible connection of the exhaust to the pipe coming up from the muffler. That joint is also dripping the same oily blackish fluid which is dripping onto the top of the fan gear box. I can see where the fluid runs off the fan gear box onto the fan shaft which then slings it backwards onto the drivers side engine door. I admit, when looking at it on the door, it does not look exactly like oil but it does have some of the sticky, thick properties of oil.

Clifford, there is no smoke coming off the exhaust pipes where this fluid is in direct contact with the exhaust system. I am also curious how you use the "UV flashlight, dye and goggles" to find leaks. I can only assume you put the dye in the engine oil, right?
Ace, there is no wetness of the tailpipe.

I drove the bus to the cabinet shop just four weeks ago and when I got it on the road for the first time in 5 years, it smoked like a mosquito fogger for the first 2-3 miles but then cleared up and hasn't smoked since. It had not been run in 2-3 years before running it then. I don't drive it very far on the road because it is registered in my name but not licensed. In MO, to keep it licensed, I would have to have it inspected every year to keep it licensed and there have been times in the past 5 years when it would not have been road worthy due to the conversion. I took a chance of getting it to the cabinet shop since it is just 5 miles from my house and drove without it having a license on it.

I have run the bus for a hour on fast idle twice over the last 4 weeks because I drained the antifreeze and added coolant cleaner to flush the cooling system BUT, before you jump to conclusions, this problem was present when I bought the bus 5 years ago and I am just now digging into it. The drivers door was covered in thick oily black sludge which almost made me not buy the bus but I thought in looking at it, it was probably the fan gear box that was leaking and it is an 8V92 afterall, so I didn't worry to about it.

After degreasing the engine and installing the "o" ring on the fan gear box dipstck, it is clearly not coming from the gear box but dripping out of the exhaust joints. I also noticed one other thing tonight that I didn't notice before. The joint between the right bank exhaust manifold and the "Y" exhaust pipe coming up to the turbo has a similiar stain, althought not as much as what is dripping out of the exhaust pipe but there is no leak at the "Y" joint before going into the exhaust side of the turbo.

All in all, reading and rereading the posts, I think my problem most relates to the "unburnt, soot and oil" mentioned below but I can hardly believe it can happen with only two hours of fast idle in the past year AND the problem was there from 5 years ago before I even bought the bus when it was being used a casino runner in Jacksonville FA and before that Las Vegas. I do know the engine only has 86,000 original miles on it since new in 1991, which I was hoping would be good thing, maybe not.

The bus has the headlights, tailights or clearance lights covered right now because I am polishing the stainless steel and preping it for primer, so it will not be able to be driven anytime soon and I still have the issue of no license, so if it is an "unburnt fuel, soot" problem, I will have to find out for sure later.

Always willing to entertain other solutions if someone thinks of something else I should check.

Rob
91 Prevost LeMirage XL
Missouri
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robertglines1
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« Reply #10 on: October 13, 2010, 06:47:16 PM »

I  replaced a push rod on exhaust valve last year and got lash to tight and it did the same thing leaking un or partially burnt fuel because the valve was not seated..re adjusted valve and all is well now...89 prevost 8V92..for what it's worth    Bob
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Ace
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« Reply #11 on: October 13, 2010, 07:32:32 PM »

Well I have to say that you have provided a LOT more information in your latter post than you did in your earlier post when you stated oil was dripping out of the exhaust pipe coming from the turbo!

Now it sounds more like an internal problem where the fuel is NOT being burnt and overloading the pipes.

Goes to show you that having these things sit for long periods does them absolutely no good!

Good luck!
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Ace Rossi
Lakeland, Fl. 33810
Prevost H3-40
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