B7100-Oil (not smoke) out of breather tube

[Sideofabarn]

My 1500-hour 2WD HST B7100 has sprung a leak recently!

This machine starts easily and runs like a top. Only normal smoke on startup and under load. No strange sounds and has never used any oil.

Two weeks ago I was pushing some light brush around with my snow plow. I was definitely putting a load on the engine but nothing harsh. When I went to put the tractor in my garage I noticed oil had leaked out of the breather tube onto the plow frame. I checked the oil and it looked a little low. I could not see or smell anything else in the oil and it looked normal (not cloudy). I don't think oil has ever leaked out of this hose in the past.

My neighbor used the tractor today to pull a heavy roller around his yard to flatten high-spots. It definitely puts a load on the tractor but again-nothing extreme. Again, oil (not smoke) came out of the breather tube. I checked my oil dipstick and oil looks normal but about 1/8 quart low. I checked the hydraulic fluid level-looks normal. The coolant level in the radiator looks normal as well.

Any ideas?

I have basic tools so I would need to use a machine shop for anything major.

Thanks in advance for your help.

 

[Lencho]

How old is your tractor? Does it have 4 or 6 bolt front wheels? I am at 1100 hours and no oil out of the breather. Wiser folks than me will chime in but it is nice to get an idea of years as well as hours.

 

[Sideofabarn]

My tractor has the 4-bolt front rims.

The serial number is B7100-B10565

 

[North Idaho Wolfman]

When was the last time you changed oil and filter?
What type and weight oil did you use the last time you changed it?
and what filter did you use?

 

[Sideofabarn]

The last oil change was 17 hours ago.

Oil: Rotella 10W-30 synthetic
Oil Filter: Fram PH3593A

 

[JeffL]

I have not have this problem with a Kubota but is fairly common on diesels. The breather filter is dirty and not draining back onto the head. The little box where the tube comes out contains the filter. The filters are usually wire mesh or multiple porous metal plates. Remove and clean with kerosene or brake cleaner. At least that is my best guess! Jeff

 

[Lencho]

If I am reading tractordata.com right then yours is a very early model - 1976 production. Do you agree NIWolfman or other members? If so the hour meter may be less important than a compression check. Can you obtain one?

 

[North Idaho Wolfman]

Had you been running the same oil in it before?
Yes that looks like an old model of B7100, might be it's just in need of some rework.
Yes my next suggestion too, would be a compression test.
While no smoke is visible out the breather is it pushing air?
Put your finger over it and check, little is normal a lot and you have a problem.

 

[Sideofabarn]

Wolfman,

I just got home from work and started up the tractor. Yes, I've been using this same oil and oil filter setup for about the last 200 hours. I change both every 35 hours and check oil level every time I run it.

I ran the tractor at both idle and full throttle and there is very, very, little air coming out. I can just barely feel a pulse when I completely block the hole with my finger.

The only oil was the residual amount in the breather tube from earlier. It seems like the oil only comes out when the tractor is under a pretty good load.

Please let me know if you need anything else.

 

[KuB2650]

Completely normal for a diesel to have some oil coming from the draft tube / breather, especially if they are run hard. Especially older engines.

 

[North Idaho Wolfman]

Yea, I would pull the valve cover and use some brake part cleaner and clean out the screen and see how it does.

 

[Sideofabarn]

Wolfman,

Is the part that needs to be cleaned #003 in the attached pic?

Although a prior poster said this oil is normal, especially since this is an older tractor, I don't think it is for two reasons.

1) this tube was always bone dry over the last 150 hours even under a load

2) at the current rate of oil lost, I would need to add a quart of oil everytime I filled up the gas tank if I was towing something heavy or plowing my garden.

 

[JeffL]

Yes, clean #003 this is the wire mesh.
also clean #001 the bottom plate with the drain holes.
On the old auto diesels these should be cleaned every oil change. The baffle is there to catch the oil mist made by the valve train and drain it away from the vent tube.
High blow by will over power this baffle and push the mist into the tube allowing oil to drain from the tube.
Try a test and extend the tube up into your view. Work the tractor and watch. Under certain loads/conditions does the tube start blowing oil?

 

[Sideofabarn]

I pulled the valve cover and pulled #001 and #003. They were completely clean-not a spec of dirt or carbon.

I ran the engine at idle and high speed with the valve cover removed. The only oil flowing was through the lifter arm journals. No oil was being blown up from the valve rods.

One idea. I've been using the synthetic rotella oil the last two oil changes. Since this is a machine from 1976-would non-synthetic oil maybe prevent/reduce this?

 

[North Idaho Wolfman]

I pulled the valve cover and pulled #001 and #003. They were completely clean-not a spec of dirt or carbon.

I ran the engine at idle and high speed with the valve cover removed. The only oil flowing was through the lifter arm journals. No oil was being blown up from the valve rods.

One idea. I've been using the synthetic rotella oil the last two oil changes. Since this is a machine from 1976-would non-synthetic oil maybe prevent/reduce this?

I'm thinking synthetic is fine, but changing to 15w-40 would give it a little more body to keep it from vaporizing and ending up in the vent.
If you do drain the oil check for heavy diesel smell as that could be thinning the oil and causing issues.
Also check for any water in the oil (it will be at the bottom of the pan) as it will cause it to do the same thing.

 

[JeffL]

Everything looks very clean. Did you clean the wire mesh? The mesh is very dense and you really don't know what is inside. Clean on the outside and solid on the inside! Maybe not, but you do want to eliminate the part 100% from further consideration.

 

[Sideofabarn]

Jeff-Yes-cleaned the wire mesh but there was zero carbon or dirt in it to begin with. I just put it back in place before the pic.

 

[clay45]

Make sure you have a clean air filter too.

 

[85Hokie]

My 1500-hour 2WD HST B7100 has sprung a leak recently!

This machine starts easily and runs like a top. Only normal smoke on startup and under load. No strange sounds and has never used any oil.

Two weeks ago I was pushing some light brush around with my snow plow. I was definitely putting a load on the engine but nothing harsh. When I went to put the tractor in my garage I noticed oil had leaked out of the breather tube onto the plow frame. I checked the oil and it looked a little low. I could not see or smell anything else in the oil and it looked normal (not cloudy). I don't think oil has ever leaked out of this hose in the past.

My neighbor used the tractor today to pull a heavy roller around his yard to flatten high-spots. It definitely puts a load on the tractor but again-nothing extreme. Again, oil (not smoke) came out of the breather tube. I checked my oil dipstick and oil looks normal but about 1/8 quart low. I checked the hydraulic fluid level-looks normal. The coolant level in the radiator looks normal as well.

Any ideas?

I have basic tools so I would need to use a machine shop for anything major.

Thanks in advance for your help.

A little different story - but more or less that same concept. On older style tractors, and I am using the Ford 8n series as an example - the air filter was a oil bath. We have all seen them before, neat concept (had a few hiccups) but the concept was, as air is forced through the oil bath, all the small foreign matter was caught by the wet sticky oil. The oil would then be drawn up into the breather pipe where is would hit the wad of steel mesh, the oil would stay on the mesh and continue to grab small matter that came by it - and as the tractor came back to idle or cut off, the particles would drop. I say all this because IF a lighter weight oil was used, (it called for straight 30 weight) the oil had the ability to get sucked up the pipe and burned!

Somewhere along your lines, the oil is getting hot and thin - to the point that it is vaporizing and then hitting the mesh and still being expelled back as a solid. Synthetic is wonderful stuff, and one huge advantage is that it pours great in cold, and the viscosity of synthetic is far less than dyno oil, which is good and in this case perhaps bad.

Question for you -

if you start up your machine, give it a little warm up and then work it hard, will it spit out the oil? OR does this do it ONLY after a complete warm up? I am sure that you know, the oil gets thinner and thinner as it heats up, the thinner the oil the easier it is to be expelled. One thing to keep in mind, ALL weights of oil, once it reaches a certain point of heat, will behave the same viscosity wise.

You might need to do a compression check - seems that you have a bit of blow by, thus increasing the crankcase pressures.

 

[JeffL]

A unloaded diesel engine even at full rpm produces low cylinder pressure. Poor or compromised rings can still seal and have little or no blow by. As the load increases, more fuel, so does the cylinder pressure. Good rings will have some blow by at max power. Poor sealing rings will start leaking at an increasing rate with load.
Try the placing the end of the tube in view and watch it as you work the tractor. Might reveal the direction to take.