KUBOTA D750 - Blowby Problems?!? Who can help?

Kubota D750 = 3-cylinder air-cooled diesel engine with 762 ccm displacement, bore of 68 x 70 mm, and a power output of 16.5 hp/12.1 kW

Hello everyone!
I know that this actually doesn't belong in this forum, but no one else has been able to give me anything helpful so far, so I'm trying here in a rather desperate way.
For the past few days, I've been using an older Bobcat with approximately 3500 hours for work in my own garden.
So far, everything seems to be okay. The initial test run during the purchase was also uneventful, but he has now already cleaned my garden twice with motor oil. Whenever I need more power and let it run at almost maximum RPM, the oil dipstick comes out and it sprays engine oil from the oil pan.
It seems the piston rings are worn and need to be replaced: The blow-by gases are probably responsible for the mess. Even when pulling out the oil level indicator on a slow-running door, the same result occurs!

What I, however, don't understand at all and is why I'm asking you is why the engine isn't venting through the vent. Could it be blocked? Or does the brown hose that comes off the valve cover need to be connected somewhere? I can't see anything, but it seems to me that it's "broken off". And also, I'm surprised that a hose that is supposed to be used to pump oil from the engine in case of an emergency simply hangs down in the air.

Wouldn't it be better to connect it to the air supply (possibly also to the silencer) instead? If so, where can I find them?

Thank you already for your answers

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Kubota D750 = 3-cylinder air-cooled diesel engine with 762 ccm displacement, bore of 68 x 70 mm, and a power output of 16.5 hp/12.1 kW

I've already answered the question about the blockage myself. I removed the exhaust and valve cover and examined the vent more closely. There's a plate attached inside to prevent oil from coming out directly. There are two fittings attached externally: one (blue) that's attached to the brown hose is closed with a worm screw - I have no idea what the purpose of this is! And the other, which has already been partially modified with a grinder, is connected to a hose that's inside the air intake hose. Everything blown clear with compressed air - everything is clear (except for the one with the worm screw if you turn it in completely as it was!)
Conclusion: There should not be any significant overpressure in the valve cover!

BUT: Why in the oil pan???? Today, for example, the oil level indicator "spiked" even after I had only briefly run the excavator at medium speed. There was a tremendous amount of pressure, and if I hadn't blocked the measuring rod, a lot more oil would have come out.

WHAT'S WRONG???? Does anyone have an idea?

LG

Hi,
The missing crankshaft oil drain is clearly evident.
If there isn't actually another connection for the vent hose on the engine block, could it be that the hose should go to the fitting of the oil level indicator (with the thread)?
hg
Herbert

Wrong measuring stick and brutally overcrowded?

Hi, Gnasch

Hello,

The screw that closes the ventilation cannot be like that. On a friend's farm, there is a skid steer loader.
which has the same engine. There was already something there, and there definitely isn't a screw in it; it's open, and a hose goes towards the floor.
There is also some gas escaping from the machine at the workplace. The smaller one goes towards the air filter, where the oilier air will likely flow.
In older commercial vehicles, it is normal for the KGE (Gross Vehicle Weight) to go "out into the open".

Greetings, Mpire

Good evening,

What model is the Bobcat loader? X250?
I have one myself and can take a look tomorrow. However, 3500 hours is also a significant number for the small 3-cylinder engine. Due to so much pressure in the crankcase, a piston could also be cracked or the head gasket could be leaking towards the oil circuit.

Best regards,
Thilo

Thank you all for the information. I will be away for the next 6 days and will not be able to resume troubleshooting until early June.
Greetings