Help with my 6V92 problem

[darrenayres]

I have a '82 MC9 that runs strong it just blows a gallon of oil every 90 miles out the blowby tubes and down the 'front' of the block. Not a lot of smoke from the exhaust though. Drove it 700 miles like this at 70 mph.

[tomhamrick]

I just fixed two minor leaks on my 6V92 by tightening the metal bands on the rubber crossover hoses that connect the head to the block. These hoses are only about 3 inches long and maybe 1 1/2 inches diameter hose. But they are special and have a raised center so they can be replaced. Anyway, if the bands on these hoses get loose they will start to drip. The one I just fixed is located underneath the pipe from the turbo to the blower. I tried to tighten it with the pipe on and just managed to make the leak worse (which was a good thing because then I was certain that was my leak). I took off the turbo pipe tighten the bands good and no more leak. The oil in these things has a way of running down hidden cracks and crevises so it is hard to see the source.
This may not answer your question directly, but then again the slobber tubes may not be the problem. If they are, some of the guys here have tied a gallon milk jug under the bus and routed the tubes into them. This will at least let you be sure if that is your leak.

[ChuckMC8]

Darren,
  first congratulations on your MC9. There are a couple of things to consider with your oil consumption situation.
First,make sure that you are using the correct oil type, a straight 40W, not a  multi grade oil.(like 15W40)
Next, make sure that you are not overfilling the crankcase. I think the best oil level is halfway between the full and add marks. Check it after the bus has been sitting all night before cranking the engine to see where the level is. Also, the dipstick has a collar on the handle that goes over the dipstick tube. Mine was bent and didnt allow the dipstick to completely seat as it should (about 2 extra qts!)
  If you haven't changed the oil, it would be a good idea to start fresh with what you know is the correct oil and the correct amount in the crankcase. The DD manual says to wait at least 20 minutes after shutting down the engine to check the oil.
  If the crankcase is overfull, it will blow it it out........I hope this helps! Chuck Lott Douglasville Ga MC8

[NJT5047]

First thing is to let it cool down before checking the oil level. I takes a long time for the oil to get back into the pan. 
May be worthwhile to get the oil level between the low and full marks, drive the bus out 50 miles and back.  Park it in exactly the same place. Let it sit overnight and see what you have.  Adding oil to a hot engine may overfill it.  If it touching the dipstick, it's safe for the time.   Often the oil consumption is exagerated.  You may be overfilling and it will lose that overfill. 
You'll have to get it cleaned up to see where the oil is leaking from.   Shouldn't be much coming from the airbox drains.
Whatever you do, don't block the tubes.   Is the road draft tube dripping oiil?  Any smoke...blue or white  smoke.
If the oil is dripping off the bell housing, suspect a rear main seal. That will make a huge mess.  I had to replace mine. 
Clean'er up and see where the oil is leaking from...that's your other "first" step. 
Let us know what's leaking and we'll give ideas on how to fix. 
Cheers, JR 

[darrenayres]

Thanks for the suggestions. Unfortunately, I've already been there. Coming back from New Orleans to Tampa, I went through 20 gallons of oil. When sitting still and idling, it will puddle up fast on the ground. 90% of it is coming through the tubes from the air boxes. I've talked with local mechanics who all want to do an inframe rebuild. However, a couple of guys I've talked with on the phone say it may be the blower since she's not blowing much smoke out the exhaust and there seems to be little loss of power if any. What do you guys think...inframe or blower rebuild?

[Geoff]

Oil out the airbox drains is typical of a 92 when it needs rebuilding-- the oil control rings are weak.  Also typical is that the engine will still run good as the compression rings are still working okay.  The blower is another possiblity, but not likely.  It is simple enough to remove the top air inlet off the blower and see if the rotors are oily. 

--Geoff

[darrenayres]

Thanks, Geoff. I'm considering one of Mike's contacts for a used 6V92 in California. Need to find out shipping costs. I have a mobile mechanic that will do the swap out pretty reasonably.  Darren

[Denny]

I had the same symptoms but not quite that bad.  Got the same response from Geoff and had it rebuilt two years ago.  I don't know where you live but if it is in So. Calif. and you decide to rebuild it I found a good shop in Bakersfield. It is Delany & Ahlf (661)322-5064.  They are really good with the 92's.  I have had problems in the past finding mechanics that really know the older Detroits.  Talk to Jerry Hampton  the service manager.  My 04 is there now getting it tuned up.  It is somewhat of a pain (gas prices) going from Orange County to Bakersfield but when you get a shop that is really good I have to go for it.

Denny

[darrenayres]

Thanks, Denny. I'm actually in Tampa, FL but would consider buying an engine out of Calif. if the price and shipping is right.  Darren

[Busted Knuckle]

Oil out the airbox drains is typical of a 92 when it needs rebuilding-- the oil control rings are weak.  Also typical is that the engine will still run good as the compression rings are still working okay.  The blower is another possiblity, but not likely.  It is simple enough to remove the top air inlet off the blower and see if the rotors are oily. 

--Geoff

As almost always I have to agree with Geoff, on this and add a note that if it were the blower and the rotors were oily most likely would smoke quite a bit as it would be burning oil also! I'd say chances are it needs rebuilt! I'd also say chances are by reading the statement, and putting a little first hand experience along with it, I'd guess the bus was worked on Hurricane Katrin releif where it sat running non stop idling most of that time and this i what killed yer engine, just a guess but it happened to us also! Under those conditions when thre driver is on call 24/7 and literaly living on the bus for weeks on end it's hard not to run it for A/C as it was unbearable down there with out it, nd if ya tried to open the windows for fresh air at night the LA state birds (mesquito's) would carry you outta da bus! As always just my 2 cents worth, and nothing else!
Knuckle

[belfert]

As almost always I have to agree with Geoff, on this and add a note that if it were the blower and the rotors were oily most likely would smoke quite a bit as it would be burning oil also! I'd say chances are it needs rebuilt! I'd also say chances are by reading the statement, and putting a little first hand experience along with it, I'd guess the bus was worked on Hurricane Katrin releif where it sat running non stop idling most of that time and this i what killed yer engine, just a guess but it happened to us also! Under those conditions when thre driver is on call 24/7 and literaly living on the bus for weeks on end it's hard not to run it for A/C as it was unbearable down there with out it, nd if ya tried to open the windows for fresh air at night the LA state birds (mesquito's) would carry you outta da bus! As always just my 2 cents worth, and nothing else!

Can't the 6V92 be idled without hurting it if the RPMs are high enough?  Truckers spend hours a day idling at truck stops with no problems I know of.\\\\

I hope you got paid a lot for Katrina duty if it cost you an engine.

Brian Elfert

[Dallas]

As almost always I have to agree with Geoff, on this and add a note that if it were the blower and the rotors were oily most likely would smoke quite a bit as it would be burning oil also! I'd say chances are it needs rebuilt! I'd also say chances are by reading the statement, and putting a little first hand experience along with it, I'd guess the bus was worked on Hurricane Katrin releif where it sat running non stop idling most of that time and this i what killed yer engine, just a guess but it happened to us also! Under those conditions when thre driver is on call 24/7 and literaly living on the bus for weeks on end it's hard not to run it for A/C as it was unbearable down there with out it, nd if ya tried to open the windows for fresh air at night the LA state birds (mesquito's) would carry you outta da bus! As always just my 2 cents worth, and nothing else!

Can't the 6V92 be idled without hurting it if the RPMs are high enough?  Truckers spend hours a day idling at truck stops with no problems I know of.\\\\

I hope you got paid a lot for Katrina duty if it cost you an engine.

Brian Elfert

Sure you can idle your engine.
No problem.
Except.........

The engine will lose lifespan.
It will cold stack, which means it will smoke white until it burns the unburned fuel out of the exhaust.
You will lose fuel mileage.
Engine parts will wear from too little oil.

The reason you see drivers idling in truckstops is that they are company drivers. They get paid BY THE MILE. Not by how much fuel they save.
The company pays for the fuel, they stay warm or cool, and all are happy.
When I was an owner/operator, I made sure I didn't run my engine any more than I had to. I put in an Arctic Fox fuel heater, 5KW Honda Generator, Webasto, and anything else I could think of to keep me warm or cool without running the engine. Including, having screens made for my truck that fit perfectly.
IHTH
Dallas

[Busted Knuckle]

Can't the 6V92 be idled without hurting it if the RPMs are high enough?  Truckers spend hours a day idling at truck stops with no problems I know of.\\\\

I hope you got paid a lot for Katrina duty if it cost you an engine.

Brian Elfert

Yes Brian truckers Idle all the time but there aren't many trucks still running 2 stroke engines anymore! Idling is hard on any engine, but it is really hard on 2 strokes! Also as Dallas mentions drivers don't care what happens to the engine as long as they are comfortble, it's the owners problem to pay for repairs! But even as an owner it was too miserble down there not to run the A/C where we could be comfortable and rested at anytime they knocked on the door and told us we were headed here or there! And last but not least yes it cost us an engine but some days paid $1050 and some paid $750 and they supplied fuel so I'd say we did ok with our buses that we had down there for 38 days! And the one that hd to come home early to run a charter after 19 days did alright also! Just my 2 cents worth which will buy a gallon of fuel if you add $2.98 to it! LOL!
Knuckle

[akroyaleagle]

I copied this somewhere but thanks to the Author and whoever posted it.

Your question ranks right up there with the most commonly asked questions we
receive. It is also, at least in my opinion, the most commonly misunderstood
aspect of the operating parameters of a diesel engine. The short answer is we
have always recommended that if the engine is going to be idling, low idle,
longer than 5 minutes that it be shut off. The reasoning is a little more
complicated but without getting into engineering 101 basically the following is
the layman's reasoning.
Diesel engines were designed to operate at peak efficiency running wide open. As
there are no spark plugs cylinder temp., obtained by compressing air in the
compression cycle, is necessary to ignite the fuel. At low idle the cylinder
temp. drops leading to incomplete combustion. This incomplete combustion leads
to carbon build up on the valves, in the oil (crankcase), on the fire deck of
the head and the dome of the piston along with fire rings on the piston. Engine
"slobbering", what appears to be oil, out of the air box drains and the exhaust
are other side effects. As worn oil control rings will also give you both of the
last two items this is often cited as the cause of an engine "slobbering". The
irony is that the carbon build up in the oil will lead to worn oil control
rings.
Now the reasons folks give for letting the engine idle. "I need to keep up cab
heat / AC in the winter / summer". If you going to be away for less than 10
minutes the engine will keep more heat being shut off than idling for that
amount of time. The AC unit will not maintain temp at low idle. "Truckers all
leave their rigs running while at a truck stop". They aren't paying for the fuel
or the repairs. "When you've been running all day you need to let the engine
"cool" down for at least ten minutes before shutting it down". Simply not true!!
I hope this has been of some help to you. If I can be of any further assistance
please contact me.
Mike Meloche
Senior reliabilt Sales Manager
Cell: 609-932-0253
Fax: 856-667-7024
E-Mail: mike.meloche@detroitdiesel.com