I changed my oil amongst other things while I had my bus in the shop this week. I filled the filter and then the crankcase with 6.5 gallons of 40w cf2 diesel oil. I ran the engine for 5 minutes, let it set overnight. I checked it again this morning the level on the dipstick was perfect and ran it to air up the bus for some additional work we needed to do. When we were under the backend putting on some new roll bar links we found 2 9-12 inch puddles of oil that looks like it blew out of these 2 small tubes coming down on each side of the engine next to the bell housing. Is this normal or should I be looking for another issue?
Jason
Do you mean the airbox drains (sometimes called "slobber tubes")?
John
maybe, I didn't follow the tubes up. There is 1 small tube, approximately 5/8 od coming down on each side of the oil pan near the transmission.
Jason
Those are air box drains did you idle the engine for a long period ?
Yea, those are the air box drains. They drip oil laden moisture out of the air boxes surrounding the cylinders. This is normal. You probably have check valves on them that close at higher pressure, so they only drain at idle. They close at higher rpm. They drip more if idling lots. Idling is to be avoided when possible.
JC
Clifford beat me to this. You need the DD service manual for your engine.
Where is the best place to get that manual?
Thanks,
Jason
Look on ebay. Some vendors have the manual on CD. Not as good as the paper book, but workable, and a lot cheaper. It is called: Detroit Diesel Series V 92 service manual.
JC
I'm with JC on liking the hands on printed manual.
But more and more it's getting hard to find them these days.
So I have learned to print the "section" on what I am working on and take it to the shop w/me. It sure is nice not to be leaving greasy paw prints in expensive paper manuals!
;D BK ;D
Here's another less expensive (OK, free) option for the 6V92 service manual: http://www.wanderlodgeownersgroup.com/downloads/DETROIT%2092%20SERIES%20ENGINE%20SERVICE%20MANUAL/ (http://www.wanderlodgeownersgroup.com/downloads/DETROIT%2092%20SERIES%20ENGINE%20SERVICE%20MANUAL/) I plan on printing it all and putting it inside plastic sleeves just like all the other info I've accumulated so far, then I'll have my own manual. There's a wealth of other useful info on the Wanderlodge downloads site, plenty of which is applicable to buses like ours.
John
And here's Detroit's suggestion for an airbox drain canister kit: http://www.wanderlodgeownersgroup.com/downloads/Detroit_Diesel_Tips_Modifications/DETROIT%20DIESEL%20AIR%20BOX%20DRAIN%20KIT.pdf (http://www.wanderlodgeownersgroup.com/downloads/Detroit_Diesel_Tips_Modifications/DETROIT%20DIESEL%20AIR%20BOX%20DRAIN%20KIT.pdf) I've done something broadly similar but cheaper - a few feet of 3/8" OD plastic air line from each airbox drain valve to a gallon plastic jug hidden inside the rear bumper, with short lengths of clear vinyl tubing going through the jug's cap so I can easily see exactly how much slobber is flowing at idle. It cost me less than $5, and it works just fine.
John
Quote from: N31569 on January 13, 2017, 03:04:11 PM
I changed my oil amongst other things while I had my bus in the shop this week. I filled the filter and then the crankcase with 6.5 gallons of 40w cf2 diesel oil. I ran the engine for 5 minutes, let it set overnight. I checked it again this morning the level on the dipstick was perfect and ran it to air up the bus for some additional work we needed to do. When we were under the backend putting on some new roll bar links we found 2 9-12 inch puddles of oil that looks like it blew out of these 2 small tubes coming down on each side of the engine next to the bell housing. Is this normal or should I be looking for another issue?
Jason
Oil out the air box drains is not normal. While there are oil catch systems available, they are only a stop-gap solution to the fact you have an engine problem. You probably have worn out oil control rings since it is coming out both sides. An in-frame or out of frame rebuild is in your future as the oil loss is only going to get worse.
--Geoff
Quote from: Geoff on January 15, 2017, 08:41:51 AM
Oil out the air box drains is not normal. While there are oil catch systems available, they are only a stop-gap solution to the fact you have an engine problem. You probably have worn out oil control rings since it is coming out both sides. An in-frame or out of frame rebuild is in your future as the oil loss is only going to get worse.
--GeoffCome on Geoff !! Don't scare this guy to death LOL. After all if these things were not meant to drip, why would Detroit have went to the trouble to have installed these drains to start with! Had an acquaintance that Owned a Wonder lodge .He kind of thought the way you do ,so he had an in frame done to about the tune of 20 grand and guess what ! It leaks worse now than it did before !!
I don't get much out of my "slobber" tubes. And my 8V-71 has high compression pistons with turbocharger. If you're getting that much oil out of the tubes, then, yes you're getting ready for an overhaul. But-don't do a rebuild-which is just blindly replacing all components with new. Rebuilding will be the only way a shop will guarantee the rebuild. Overhaul is just replacing what is worn out-in this case you might be able to get by with just a ring replacement, bearings, and check the heads for cracks, with valve job.
When I was driving truck, I had my 8V-92TA rebuilt at 500,000mi. At that time, the cylinders still had cross hone marks and they said I could get by with just a ring replacement. But-Detroit had come out with newer piston and cylinder design that reduced oil consumption, so I had the newer kits installed. As a result, my oil consumption went from 1,200 miles per gallon to 2,200.
Now is the time to get the engine back up to good running. Good Luck, TomC
I would drive it and warm it up. Drive it hard for an hour. Then come back, and let it idle at high idle and see if it drips out the drains. I won't call them slobber tubes cause I value my life.
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oil is cheap ;D
Quote from: eagle19952 on January 18, 2017, 08:01:15 PM
oil is cheap ;D
Oil is cheap, but the mess on your toad and the back of your bus isn't easy to get off.
Oh, and the term "sl**ber tubes" is a misnomer created by truck drivers back in the day, just like "318" meant an 8V71 rated at 318HP, although they were really only rated at 304 HP with the standard N65 injectors.
--Geoff
If oil is getting on the toad and on the back of the bus ,there is definitely a larger problem because if this is happening it is "slobbering"when the bus is in motion.Mine will drip a bit a slow idle but if you go to fast idle or put the bus in motion the dripping will disappear almost immediately.Another thing that I have found out about the 8V92 is that if someone slips up and puts multi viscosity oil in one of these things ,it is almost like driving pt with the drain plug removed .
If oil is coming out of the airbox drain tubes when driving, it probably indicates that the two airbox drain valves are not closing when the engine is at more than idle. Inside the valve is a spring-loaded disk that allows air to flow through at low idle, but at higher pressures such as above fast idle it should block airflow. These valves can get grunged up inside so they never close properly - I suggest removing each valve, disassemble and clean, then reinstall with a slight down slope to where the 3/8" hose attaches to its output. If you have a short length of clear tube in the drain tube to the collection container you can then easily see what each airbox and drain valve are doing at different engine speeds.
John
There are 3 different valves the 900 rpm closing ,1000 rpm and the 1200 rpm the new valves are non serviceable fwiw
I should have mentioned when the oil control rings get weak and start pumping oil into the airbox, you have excessive blow-by so oil leaks out almost everywhere there is an old gasket as well as the air breathers. Even more so with the check valves closed. The older Detroits didn't use check valves, and it is a 92 Series old oil ring problem. The 71 Series lose compression when they get tired, the 92's start pumping oil when they get old but keep their compression longer.
--Geoff
Quote from: Geoff on January 20, 2017, 04:51:01 PM
Oil is cheap, but the mess on your toad and the back of your bus isn't easy to get off.
Oh, and the term "sl**ber tubes" is a misnomer created by truck drivers back in the day, just like "318" meant an 8V71 rated at 318HP, although they were really only rated at 304 HP with the standard N65 injectors.
--Geoff
So, I have drove the bus 75 miles to bring it home. The oil level is still at the full mark, I don't have any puddles now when it idles (just that one time). But I did notice some air blowing out of the one tube on the passenger side. I didn't notice it so much in the drivers side. Is this normal, or should I be looking at something else?
Jason
Jason, sounds like a good and healthy engine to me. It was slobbering at first because of idling. Then you take it out for a good run and cleans up. All is good now. The one side blowing more is probably the check valve. Take it out, clean it, or replace it.
JC
Thanks, I'll do that.
Jason
So it was 5 minutes of idling that caused the engine oil to drop out of the air box drains too long? I have an engine air box catch cannister and might get a table spoon of water and oil out of it in 5,000 miles. And I idle it a lot longer than 5 minutes. The cannister came with the bus, and the engine has 75,000 miles on it since a complete overhaul.
--Geoff
Quote from: luvrbus on January 21, 2017, 07:12:56 PM
There are 3 different valves the 900 rpm closing ,1000 rpm and the 1200 rpm the new valves are non serviceable fwiw
Are there markings or part numbers on them to distinguish which check valve you have? I got some as part of a kit, and there was no mention of what level they were. Should I assume the 900 rpm would best if fast idle is 1000?