John Deere 770 diesel/oil issue

   / John Deere 770 diesel/oil issue
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Mattyboy93

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I’ve heard that injection pumps can leak into the oil... but unsure if that’s the issue.

Only other thing coming to mind is stuck or bad injector... but I feel I’d be able to hear/feel that..

I may crack the drain plug on the oil and see what the color is. The old owner had off-road diesel in it. Since I just changed the oil it might be tinted red if it’s fuel...

It’s not coolant bc it’s not milky

I don’t believe it’s hydraulic fluid since it has a slight diesel smell I feel... but if it turns out not diesel then it’d have to be that.

It’s definitely thinned since I changed the oil and I’ve only driven it 2 or 3 times since that for maybe 10 minutes after letting it idle for a minute...

It was mentioned that the short run time may have caused that? I don’t know enough about diesel to know if that could cause that.

Would the thinned oil cause it to leak from either the blow off hose off the top of the engine or possibly lower crank pulley area?

Do they make rebuild kits for the JD 770 injection pump?
 
   / John Deere 770 diesel/oil issue
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Mattyboy93

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Is the dipstick level increasing?
The fluid on the steering cylinder is most likely coming from the breather hose off the valve cover. It will emit some smoke, oil mist and water vapor.

Doesn’t seem to be. When checked it’s hard to tell it’s on the stick since it’s thinned. It’s still got oil in it though
 
   / John Deere 770 diesel/oil issue #13  

Industrial Toys

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Probably the last thing I would think about doing myself. Maybe have the oil anaylized.
 
   / John Deere 770 diesel/oil issue
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Mattyboy93

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Doesn’t seem to be. When checked it’s hard to tell it’s on the stick since it’s thinned. It’s still got oil in it though

I take that back. It is definitely higher and has a slight hint and smells of off-road diesel
 
   / John Deere 770 diesel/oil issue #15  

Industrial Toys

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Here. Off road diesel only has the addition of dye.
 
   / John Deere 770 diesel/oil issue #16  

Robin Veerman

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I take that back. It is definitely higher and has a slight hint and smells of off-road diesel

Go to your favourite heavy equipment dealer and get a Used Oil Analysis (UOA) kit. Follow the directions, fill in the info, and send it away and wait for the results before running the engine. Once info received plan your course of action. Keep us posted. Dutchy
 
   / John Deere 770 diesel/oil issue #17  

770

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I recently bought a 770 with 283 hrs ran it for ~50 hrs. Religiously check dip stick for color & depth.
Always thin, light color and above the fill hash marks. Though always looked good I Changed oil, JD 50 11 & filter. (Old oil black as coal as a-posed to always reading thin/clear reading on dip stick. ????)
Also flushed cooling system even though gauge always reading low, full and good color.
Then No problems for ~50hrs & now oil indicator flashing running at ~<1500rpm. Working harder at ~15000-2000rpm light goes away. Oil level dip stick reads higher than required thin & clear. (I did add a ~ 1/2 qrt to see if it would cool it down but will drain to req level tomorrow & monitor.)
Engine does not miss & sounds good to my layman's ear.
Does not smoke.
I did/do not detect any burnt or diesel smell on dip stick or at oil change. There seems a burnt spot on stick above full hash marks.
Pulls strong. Normally run/work it
bush hog, Heavy 6’ disk & fully loaded 6’ box blade for hours at a time. However now oil lightcomes on -20 minutes with or without load. If run up >1500 or better light goes off.
Can anyone help. 1st time blogger.
Thanks
 
   / John Deere 770 diesel/oil issue #18  

beenthere

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Welcome to TBN

Hard for me to sort out what you are referencing. What I interpret is you are adding to your oil in the engine, and maybe it is coming from the coolant. Or maybe diesel fuel getting in the engine oil. Others may have it sorted out.
 
   / John Deere 770 diesel/oil issue #19  

Robin Veerman

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Well, send an oil sample, like I suggested in post #16. What grade/viscosity of oil are you using? You don’t know the history of previous oil changes prior to you owning it. If the previous owner neglected to do ANY oil changes there may be an issue with sludge causing the oil pickup to become restricted? Heck it might simply be a faulty oil pressure switch, but you better investigate further instead of running it into the ground. So, Run the engine until oil is hot. Let it cool for 30 minutes and take a sample and send it away…Keep us posted. ***ps, you will need to explain that you’ve added 1/2qt of oil, which dilutes the oil/contaminates somewhat.
 
   / John Deere 770 diesel/oil issue #20  

770

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Well, send an oil sample, like I suggested in post #16. What grade/viscosity of oil are you using? You don’t know the history of previous oil changes prior to you owning it. If the previous owner neglected to do ANY oil changes there may be an issue with sludge causing the oil pickup to become restricted? Heck it might simply be a faulty oil pressure switch, but you better investigate further instead of running it into the ground. So, Run the engine until oil is hot. Let it cool for 30 minutes and take a sample and send it away…Keep us posted. ***ps, you will need to explain that you’ve added 1/2qt of oil, which dilutes the oil/contaminates somewhat.
Rob tks for sound/fast reply. Wilco when I find UAO supplies/site.
Agreed, don’t know service history.
I use only recommended JD Plus 50ll (viscosity ?).
Take care
 
 
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