I discovered this past summer that my unit drops about a half cup of oil on the ground when stopping after being on the road.

It doesn't leak when parked for extended periods or when running on the road ---- just when stopping like at a rest stop. The oil comes out or the breather hole between the engine oil pan and the transmission. The spot it leaves is about three inches in diameter. At first, I thought it was tranny fluid and even sucked out some tranny fluid overfill --- to no avail. The engine oil does go down but not very fast --- maybe a quart every 2000 miles. Everything else seems to work fine and the breather tube is not blocked. It acts like pressure is building up when on the road and the 'burp' is a release.

Has anyone else noticed a leak like this??

I have not called Spartan or Cummins about this problem yet --- it's hard to get a response on the hard ones.

Thanks in advance for your help.

quote:

Originally posted by Frank Strong:
The oil comes out or the breather hole between the engine oil pan and the transmission. The spot it leaves is about three inches in diameter. It acts like pressure is building up when on the road and the 'burp' is a release.

Has anyone else noticed a leak like this??


Thanks in advance for your help.

No diesel knowledge here, but lots of engines only leak when hot. On shutdown, many engines have oil up top that returns to the sump. It is possible that a little of this is going astray.

How many miles? M11, N14 or is it, as I suspect, an 8.3l?

quote:

Originally posted by Frank Strong:
I have not called Spartan or Cummins about this problem yet --- it's hard to get a response on the hard ones.

You'll be happy to know that this isn't hard. It does require several steps to properly diagnose.

When driving down the road, you may have pressure forcing oil to stay in the breather tube. When shut down, the oil that is in the breather tube is now able to run down the tube.

When mounting an engine in the back of an RV you have different air pressures working on your coach then in a truck, where the engine is front mounted.

If you have a rubber hose attached to the vent tube. Make sure that the hose isn't kinking, from air flow, while driving down the road. The lack of roadspeed could cause the hose to open back up when parked or going real slow.

They might, I don't know, have a different breather tube for a front or rear mounted engine. I know that most tubes are not flat, they have a slight angle at the bottom of the vent. I would suspect that if the angle was facing forward that the air pressure of road speed could be keeping the oil in the tube.

I would do this first. Remove the valve cover and make sure that the "wire mesh breather" is planted in the right area. Sometimes they slip out of their mounts. If there is nothing wrong with that, and your crank case pressure is less then 10cfm's there is another option...

Fleetguard makes an enviromental kit that attaches to breather tubes. Enviroguard OCV kits can be purchased for your Cummins engine provided that you have a way to drain the oil back into your engine.

quote:

From the PDF at Fleetguard:
If your engine application does not have an access port in the block or oil pan for use in installing an oil drain line, contact the engine manufacturer for other possible options. Drilling into the engine block is not recommended to install these kits.

These kits are usually installed in Fire Trucks. Imagine an oil drip on a Fire Truck? The Fire Chief or members would blow a gasket and demand that they address this right away or the DEC would be called in.

I'm not kidding, all fire departments that I work for have pretty much the same mindset. If a single drip comes out of anywhere it is cause for a full fledged teardown to fix this enviromental monster.

Trust me, I'm not complaining. I am more then happy to take the work. As an added bonus, these fire houses have "members only lounges" that rival the best bars and nightclubs around. If you can make friends with members at a firehouse you are invited to many free, taxpayer supported functions.

Because 99.9% of our local firehouses are volunteer, you meet many members who can give you extra work at their day jobs by word of mouth. These places are fantastic for networking in the blue collar world.

These Fleetguard kits has saved many of Fire Engine Manufactures a ton of money on forced warranty issues. They are pretty much standard spec now at most Fire Houses and School Bus companies.

On a 300 HP Cummins engine you would want to use kit# CV50203 or kit# CV50112. This is rated for a max blowby of 10 CFM measured at the vent tube.

The PDF at this link shows an 8.3l rated at 300hp that uses kit# CV50112. Make sure that you only have one breather or you'll need 2 kits to put on.

Because some of our members have a 5.9l engine, here is a link to a kit that is installed on an 5.9l engine. This one uses kit# CV50106. Even if you don't have this engine, look at that link. It shows the kit mounted on the engine that is not in a vehicle and it gives you step by step instructions.

You can read more at this link

For more information, contact Customer Assistance at 1-800-22-FILTER (1-800-223-4583), fax 1-800-999-8664, or visit them at www.fleetguard.com

~~~I must remind you of 3 things before you consider these kits~~~
1)Pull off the valve cover first and inspect the wire mesh for proper placement.
2)If the angle of the vent tube is facing forward, turn it around or cut the angle to face it backwards.
3)If you have a rubber hose attached to the vent tube. Make sure that the hose isn't kinking while driving down the road.

I think the wording in my initial posting may be misleading --- the oil is not leaking out of the crankcase breather tube. It is coming out of a hole (one inch) located at the bottom of the bellhousing that separates the engine block from the transmission. This is a location that typically indicates a rear main seal leaking problem or a similar seal in the tranny (in autos). But rear mains tend to leak all the time once they get started and this one only leaks for a short time after running.

I will double check the breather tube for blockage as this could be causing pressure buildup and maybe a release thru the one inch hole????? With the exception of a possible kink or similar, the breather tube appears to be OK. The angle of the tube is facing to the rear.

Sorry for the misleading verbage --

quote:

How many miles? M11, N14 or is it, as I suspect, an 8.3l?

Bill, I missed your opening question ---- I was too anxious to get into the meat of your great response. My engine is an 8.3 Cummins with about 78K miles. It seems to be a very tight and clean running diesel -- a minimum of smoke etc.
I have not checked the vent tube for kinks etc. yet. Will let you know soon. Smoke does come out the tube when the engine is idling while the RV is stopped. It may still have a problem when going down the road.

I have the 5.9 Cummins and have just a bit of oil coming out of the hole you mentioned and will leave a very small spot after a LONG run, I also have a small amount of oil coming out of the breather tube and haven't looked into that yet. So far it hasn't amounted to much so I will wait until it get bad to address.

100K miles

I just replaced the oil pan and gear cover gaskets that were leaking and creating a real mess on the back of the coach and the trailer.

On the trip over the weekend to Washington D.C. and back I had the exact same problem develop that Frank has and it is dripping while underway. The trailer and the back of the coach are a mess again; you may not experience the back of your coach being covered with oil because of the drafts created that I have with hauling a trailer might explain this. I could see a drip every 5' or so trailing up to where I was parked.

Have you gotten any answers about what is causing this yet?

I've been checking further into this and it appears that this leak is not uncommon on Cummins 8.3l.

It's the rear main seal.

Disconnect transmission from engine and remove flywheel to replace the seal.

What fun!!

"loses a quart every 2000 miles."
"Disconnect transmission from engine and remove flywheel to replace the seal."

Stop! Think! Relax! Leave it alone.

Gunner's advice is good.

Please accept my apologies for misunderstanding the OP's concerns. I was under the impression that the OP had a substantial oil leak (1/2 cup) originating out of the flywheel cover drain hole, as I am currently experiencing on my coach.

I did not intend to imply that diesels with no apparent leak or just a couple drops of oil in this area were in any need of repair. I also did not think that anyone would run out with a handful of wrenches and drop their tranny out on the driveway. I merely was pointing out that I was experiencing the same symptoms as the OP and discovered what the cause of my leak was and in general what was needed to repair the problem.

My coach will be at a qualified service facility on Monday, and rolling in and out of Buffalo NY the following weekend with an "oil free" trailer and backside.

Again - I'm sorry for any inappropriate information I shared.........I guess I should stop! think! relax!

Many of these threads consists of brainstorming - just throwing out ideas. Its very difficult in most cases to give a decent diagnosis with out being able to see and test the coach.

Possibilities, such as you mentioned, are nothing to apologize for, because the more ideas and options, the more likely we're likely to offer something useful.

quote:

Originally posted by Steve WI:
Please accept my apologies for misunderstanding the OP's concerns.

My coach will be at a qualified service facility on Monday, and rolling in and out of Buffalo NY the following weekend with an "oil free" trailer and backside.

Again - I'm sorry for any inappropriate information I shared.........I guess I should stop! think! relax!

I think Gunner was just pointing out that this isn't the end of the world.

He said what many of us thought to ourselves "For crying out loud, it's only a quarts every 2000 miles!"

Now I don't want to talk for Gunner, or anyone else, but I made it a point of saying in my response how certain sectors of our society is more apt to repair something like this then other areas.

Myself, I would drop the transmission and do it. But then again, I have a leg up on most here when it comes to this type of service work. For others who are pulling a toad, it just might be manditory. For most, leave it alone, monitor it, and save some money for a real problem.

It's Frank Strong who's losing a quart in 2000, & Steve WI whose coach & trailer are oil-covered. Two different members, two different problems

A quart in 2K is not likely to cover anything with oil, & a well-oiled coach & trailer are likely to represent a lot more oil loss than 1 qt. in 2K miles. I'd advise Frank to not worry about the oil loss. As Rusty has said several times, "oil is cheaper than metal."

Steve clearly has a serious problem, & he's addressing it properly. The proof of the pudding will be if his coach quits oiling up his backside & his trailer after the work is done. If it doesn't do the job, then we'll all have another problem to chew on.

Cummins customer support @ 800-343-7357 indicates that the rear main seal is probably the only source of the leak. They would not speculate on any other problem causing the leak. He agreed that it was unusual for the 8.3l to start leaking at only 80K miles and only while stopping after a run. If the vent tube is breathing while stopped, it would not likely be restricting on the road and maybe causing pressure buildup in the block.

I think the best course of action for me is to "wait and see". If it starts to leak while on the road and make a mess on the toad and other things --- then maybe I'll be motivated enough to repair. I'll bet it would cost several thousand to get fixed!!

Thanks for all the help and recommendations!