Hey I’m new to the skid steer world. I am in the process of buying a bobcat s250 from a coworker that has owned the machine since new, he upgraded to a new machine. It is an early 2000’s s250 with 1200 hours and is in very good shape being a one owner machine. It has the Kubota V3300 engine and I have found it has lots of blow by coming out behind the machine. I extended the blow by tube down lower so it isn’t just blowing out in the engine compartment. It doesn’t smoke from the actual exhaust pipe hardly at all except when idling up. When you get done running for the day and park in the shed it drips a little motor oil out of the blow by tube onto the ground so I have noticed it does use a little oil during a days work. It starts good and even starts well when it’s cold out. I have a hard time believing that the engine is worn out enough to have this much blow by with only 1200hrs and I know it hasn’t been abused. When you and working with it wide open it really sends out a stream of blow by. I’ve read about screens in the valve cover and something about a diaphragm? Any help pointing me in the right direction how to figure out what the blow by is about would be appreciated. thanks
Lots of variables at play. Your co-worker may have used some starting fluid at some point and busted a ring. Glow plug engines are especially sensitive to that. How is oil consumption? Have you verified that’s it’s blow-by and not steam? It might have an induction air leak and ingested enough dirt to dust the cylinders at some point. You could closely inspect the air intake and verify. Welcome to the HEF, Mr. Kopper. Good to have you. Nicely written post, BTW.
For example I added a touch of oil yesterday to get it exactly on the full line. Reset the hours yesterday and ran it for 3 hours parked it in the shed and checked it this morning and it was down a good 1/4” or little more on the dipstick and had dropped a few drops of oil from the extended blow by tube onto the concrete. I had guys there with me while I was grappling brush and they said it had a steady stream of blow by while running. It was definitely more of a smoke than a steam, had a little smell to it.
Gotcha.
Would a compression test tell the story? I just want to figure it out so I can decide if I should be buying or passing on this one.
The turbo could be pumping oil into the air intake, maybe. Or, contributing. That’s an easy check. But, sure. I’m a numbers guy. Let’s get all quantitative and perform a compression test. Kubota may have some base pressure specs available for the V3300. What a great engine, BTW. Hook your manometer up to the crankcase and report back.
Pull the glow plugs and stick your camera into the cylinders. Let’s look at the cylinder walls.
Seriously, if it’s a cherry one-owner machine like you say, I wouldn’t let a worn out V3300 scare me.
Just for the record, I seen a small Bobcat 543 or something like that , had only 100 hours with heavy blowbye, still on warranty, Engine Blown. It can happen,. good to do some checking as Coaldust suggested to find true cause before dropping cash. Or have a contingency fund for a worst case scenario. Always good to do quality inspection first. Not saying it is, but have seen some perfect, turn into can of worms in the past. Error on the side of caution. Simon C
If you buy it plan on replacing the engine. The only causes of excessive blowby on that rig are going to either be major mechanical damage (broken rings, melted piston, spun bearing, etc) or just being plain worn out. Hours mean nothing on equipment. A compression test can help narrow down the problem but either way its still got a problem.
I think we lost the OP. Hope he didn’t give up on his dream of being a Bobcat owner.