john deere 850 4x4

   / john deere 850 4x4 #1  

RHemmer

Member
Joined
Oct 20, 2009
Messages
34
Location
Independence Minnesota
Tractor
Kubota b2400
Recently bought a John deere 850 with alittle under 1200 hrs on it. It runs well but notice a fair amount of smoke come out from the crankcase breather tube. Seem like the tractor needs to be warmed up before this begins. What the problem. I am not much a of a mechanic. I would appreciate your thoughts
Thanks
Randy
 
   / john deere 850 4x4 #2  
When the engine is cold look for condensed moisture on the dip stick above the oil level.

When the engine is warm, pull the dipstick and try to set it a fire with a lighter, indicating fuel in the oil.

If you have either of those conditions, consult a trusted mechanic.

Good luck
 
   / john deere 850 4x4 #3  
Not sure of normal breather smoke for your vintage Yanmar diesel which is the engine in your tractor. My Cat mini-excavator has a 3 cylinder Japanese engine of similar design and power. It s a Shibaura built by Cat under license from Shibaura. It puts out a lot of smoke from the breather tube when hot and working hard, but power is very good and it uses very little oil. I have a lot of experience with the Shibaura/Caterpillar and know it is the nature of the beast. It could be the nature of the beast. However, my brother-in-law has a Deere one model larger than your tractor and he did suffer a cracked valve seat. When I looked for info on the web, I did find quite a few others reporting the same thing but that is more likely to leak exhaust gas into the coolant instead of the crankcase.
 
   / john deere 850 4x4
  • Thread Starter
#4  
Thanks you both for your input on this. I have started it quite abit lately with out letting it warm up really good. I am hoping its condensation thats built up and needs a good warm up cycle? The reality is it probably needs some motor work.
Thanks again.
Randy
 
   / john deere 850 4x4 #5  
Thanks you both for your input on this. I have started it quite abit lately with out letting it warm up really good. I am hoping its condensation thats built up and needs a good warm up cycle? The reality is it probably needs some motor work.
Thanks again.
Randy
Try to plan your work so that the engine gets a good workout.

If I don't have enough actual work to do with mine, I'll let the tractor run at half throttle for twenty minutes or so just to burn off condensation. Better to waste a little fuel than to cause premature engine wear. (IMHO)
 
   / john deere 850 4x4 #6  
These are notorious for frozen clutches; that is the clutch literally rusts to the pressure plate if tractor is layed up for extended periods creating an over thousand dollar repair. To mitigate this, find a method to keep the clutch pedal depressed if tractor is not going to be used for awhile. Amount of smoke you describe coming from breather is not normal for these Yanmar engines in the 850 series.
 
   / john deere 850 4x4 #7  
Try to plan your work so that the engine gets a good workout.

If I don't have enough actual work to do with mine, I'll let the tractor run at half throttle for twenty minutes or so just to burn off condensation. Better to waste a little fuel than to cause premature engine wear. (IMHO)
I should have said that the 20 minute run time is 'after' the initial warm up period.
 
   / john deere 850 4x4 #8  
I own an 850 with about half the hours on it that yours has. I don't have smoke coming from my Crank breather at this time. What color is the smoke, whiteish? it could be steam from a coolant leak of some sort. Keep and eye on your coolant levels and the dip stick for milky slime indicating coolant leaking some where. If not coolant, I would guess that your rings maybe getting tired and it is just plain blowby. A hard starting Diesel in the cold can be from low compression as well. Does it start hard in the cold?

thanks, Phil C.
 
   / john deere 850 4x4 #9  
I own an 850 with about half the hours on it that yours has. I don't have smoke coming from my Crank breather at this time. What color is the smoke, whiteish? it could be steam from a coolant leak of some sort. Keep and eye on your coolant levels and the dip stick for milky slime indicating coolant leaking some where. If not coolant, I would guess that your rings maybe getting tired and it is just plain blowby. A hard starting Diesel in the cold can be from low compression as well. Does it start hard in the cold?

thanks, Phil C.

I have seen these engines go 7000 -10,000 hours before any sign of blow by. Your 850 must be a real beauty with only 600 or so hours and pretty rare for such an older tractor to have so few hours.
 
   / john deere 850 4x4
  • Thread Starter
#10  
The tractor is alittle hard to start when temps dip, but I always contributed that to being a diesel trait. The smoke is grey and starts up only after the tractor is warmed up.I dont notice any coolant missing and no sludge on dipstick/oil cover. I am preparing myself for a trip to the mechanic and see what is going on. What i find odd is the smoke coming out of the beather tube but you dont really notice anything as far as excessive smoke coming from the stack?
Thank you all for your advice and thoughts!
Randy
 
 
Top