Hey gals and guys. At the farm where I work, we have an excavator with a 4BT in it. It has been spewing oil out of the breather tube and the dipstick tube. We think it may be a cylinder or more with bad rings. Any thoughts? I didn't know where the best place would be to ask this but figured you have some of the best knowledge so any ideas are appreciated.

Thanks,

Matt

 

It's called wore out, time to rebuild. Or you can run it till it sucks enough oil past the rings to run away. That'll be exciting.

 

We have 4bt in our case backhoe. The diesel return line was plumbed into the valve cover. It had a small crack and diesel was pouring into the valve cover causing oil to do what you're saying. I'm not sure if you have this feature or not. I think it was something case did back in the day. I've seen this on ford diesel motors as well where they plumbed the return inside the valve covers.

There is a update that runs the injector line outside where it should be. If that is already there then it's probably best to do what martin said.

 

First question is how many hours on it ? does it have a miss or is it running smooth still ? Is the oil over full all the time ? Does it have fuel in the oil ?
Most people dont think of an excavator motor working hard because it doesnt sound like it ever labors but actually when your operating 2 or 3 functions at once you have your pumps stroked out and workin the heck out of it. Usually between 12 and 15,000 hrs is all you ever see on an excavator engine because they do get worked so hard .

 

The return line runs outside I beleive..from each injector back towards the pump side of the engine. The oil looked fairly normal, or at least like fuel was not present in it. It started doing this after we put a stock muffler on it as it was previously straight piped. I will double check the hours tomorrow.

 

head gasket problem?

 

Ok i cant stand it any more I'm kind of an equipment guy and i dont think i have ever seen one of those in an excavator. Usually older machines have a 4-53 or something like that in the smaller machines. So what is it exactly ???

 

If it has signifacant blowby, it will tun the oil black in very short order, even as it blows it out.

Just went through this a few weeks ago on a '96 Cummins I drove back from California.
It would push ~ a gallon out in roughly 125 miles and it was always black.
I'd done a filter and oil change before I left CA with it.

Notable blowby= dark oil.

Mark.

 

The machine is a Hyundai Robex. According to the identification plate, it is a 2002 model. It has 3300 original hours only on it. The oil does appear to be a bit darker than usual, but oil out of a diesel is usually always on the darker side so it is somewhat hard to tell the difference. The oil was good on the dipstick...had an oil change not all the long ago. It didn't sound any different when running with the oil spewing out. Like I say, most of this started happening after we took the straight pipe off and installed a new stock muffler.

 

Make sure the breather in open and clear of debris.

 

Could the new stock muffler be restricted causing excessive back pressure like when a cat plugs up, compression goes out elsewhere.

 

That is a good thought Jim. I will have to take a look at that once. I guess something we should do is put the straight pipe back on and see if the issue persists.

 

Does the machine have an aspirator pipe that goes to the air cleaner? Years ago I worked for a guy that added a muffler to a dozer. It added backpressure to the aspirator and backed exhaust to the intake.

 

That's a good question. To be completely honest, I am unsure. I will have to check that out. Thanks for the suggestion.