Oil & Fuel How much should a diesel smoke?

[Bruce8989]

I bought a used (1000 hours) Kubota 2cyl B5100 diesel a few months ago. It always smoked some when started up, but then nothing visible. Now I am seeing a good size puff everytime I increase the throttle - is this normal? Do they all smoke a little? This is my first diesel - so I'm not sure.

I've changed the oil - filters etc... didn't change anything. Your advice is appreciated.

 

[looch]

Hi Bruce. What color is the smoke?

A puff of black now and again while under load or when increasing throttle is not something that I'd be terribly worried about - especially on a 20 year old tractor.

To me (and I'm no mechanic) blue smoke when hot is an oil ring/cylinder problem. When cold, it's a valve/seal issue. Again, though, a puff now and again is acceptable (to me, anyway).

 

[Rover]

No more than a pack a day!

Sorry, I couldn't resist.

New tractors are designed to smoke a lot less than older ones. So when people here talk about seeing a little smoke on a new tractor it may be of concern. Older tractors were not designed to like the new ones. Diesel engines under load smoke! Increasing the throttle places the engine under load. Ever get caught behind a buss?
It doesn't sound like yours is smoking that much.
Are you using the correct wieght and type oil such as 15w-40 and rated for a diesel engine?

Rover

 

[BurningtreeFarm]

Careful on the engine oil, yes I would agree on 15w/40 for diesel engines except when it comes to kubota diesel's, I tried the 15w/40 in my 5450 and had tremendous oil consumption, changed the oil right away with the manual recommended 10w/30 oil consumption went away and so did the engine smoke. Tim

 

[Bird]

Increased oil consumption with the 15W-40 over the 10W-30? I sure wonder what could have caused that because that's just backwards from anything I've seen or known of in the past.

 

[BurningtreeFarm]

Bird:
Thats what I thought also and part of the reason I tried the 15w/40 but had no luck and got very concerned when checking the dip stick and the oil level very noticably down after a very short period, had nothing else to go by, ie) heavy brush mowing, plowing or in general any heavy use whatsoever, changed oil and filter (both times) back to the 10w/30 and oil level stays rock solid no matter what the conditions of use might be, asked the local dealer and there answer was go with the kubota recommended, they did all the studies and test's and came up with whats in the manual, I said "yes sir" and left it at that. Tim

 

[cisco]

The 15-40W vs. 10-30W is indeed puzzling - maybe someone in this forum knows a logical answer. As to smoking, I've 80 hours on my current (bought new) L3410 - and it's been through a 50 hour oil/filter change - if it burns oil, it's negligible. So, I doubt any smoke I see is oil - just incompletely combusted fuel. My engine emits a puff of smoke when it starts, and when I do something really dumb - say, stall it when I use the FEL for an overly aggressive push into the dirt pile (GST, not HST, so I can stall the tractor - you HST folks don't have to face that humiliation - OK, it's minor, but just as the engine quits it emits a small puff of smoke - sort of like it says - take that, stupid). Anyhow, you should consider fuel combustion as well as oil leakage via valves/rings/etc. when and if you troubleshoot the smoking problem.

 

[Bird]

<font color=blue>stall it when I use the FEL for an overly aggressive push into the dirt pile (GST, not HST, so I can stall the tractor - you HST folks don't have to face that humiliation</font color=blue>

Oh yes, we do. I'll bet most of us (well, me anyway) have stalled HSTs doing the same thing. And my B2710 was the same way; little puff of smoke when it started, but didn't burn oil.