Coolant in Oil

[KubotaSteve]

I just bought a John Deere 410B backhoe. It only has 6300 hours on the meter and the hoe is tight. The front bucket has a little play.
Anyways, the engine sounds great and starts up everytime. The issue is my oil looks like a milky colored oil and it was overdilled and the coolant was underfilled so it doesn't take a rocket scientist to figure out what is happening.
With that said, I tore the top end of motor down and the head looks fine and the block looks good and the head gasket looked ok.
in the next day or so, I'm gonna tear the bottom end down to see what I can see there.
Any suggestions on how the coolant is getting into the oil? And what else can I look for?

 

[Sawyer Rob]

Cracked block, or leaking in through a corroded cylinder?

I'd double check that head gasket though...

SR

 

[SSdoxie]

Does this have an engine oil cooler, oil cooled by radiator coolant? If so that would be a place to check. Exchanger rust through and push anti-freeze into oil.

 

[adventure bob]

Before you tore it down I would have recommended a leak down and compression test. I have done leak downs on seemingly good head gaskets that actually made gurgling in the radiator. When pulled apart, the gasket looked fine. Decked the head, put it back together with a new gasket and no more crossflow. Don't know much about the 410B, is it turbo? Regardless, I would freshen everything up while you have it apart, rings, seals etc... You may get lucky and hit the culprit by simply replacing stuff. Its always slightly satisfying to pull something apart and put it back together and the problem goes away. Its also very frustrating to do it and still have the problem.

I don't envy you...

 

[houstonscott]

Head gasket, or crack head, or cracked block. Cracked block, new engine. Coolant is highly corrosive, and everything that is oiled will have to replaced. I'd dump it... Good luck. HS

 

[KubotaSteve]

I'm going to get the head tested tomorrow. After going back and looking at the torque specs for the head bolts, I'm thinking they were over torqued possibly which in turned caused the head gasket to leak. I'm also going to look into the oil cooler possibility as well.
As a ballpark figure, what is a John Deere 410B worth with 6,300 hours and a tight hoe, front bucket has reasonable play for its age. It is a open cab. I just want to make sure I'm not getting under water on it.

 

[houstonscott]

I'm going to get the head tested tomorrow. After going back and looking at the torque specs for the head bolts, I'm thinking they were over torqued possibly which in turned caused the head gasket to leak. I'm also going to look into the oil cooler possibility as well. As a ballpark figure, what is a John Deere 410B worth with 6,300 hours and a tight hoe, front bucket has reasonable play for its age. It is a open cab. I just want to make sure I'm not getting under water on it.

I'd look for good replacement engine to rebuild or drop in... HS

 

[adventure bob]

Hopefully your having them check the head for deck flatness, not just cracks or leaks.
You can find the complete rebuilds for your tractor for about $750 online. Bearings gaskets pistons, sleeves... everything.
Add about $1000 to $1500 in machine work and your there. Unless the block or head is cracked then your kinda stuck.
If your not counting your labor, you could be done with a fresh motor for about $2250.
Since you pulled it apart, I'm assuming you can put it back together.

If you have the inclination and money, deere sells everything from blocks to full up engines. I'm not sure how cost effective that would be. Another option would be a third party rebuild. Our local Cummins dealer rebuilds all kinds of motors. Again not the most cost effective, but a way to get it done quick.

 

[SimS]

When you check the bottom end, try and get a good look at the bottom of the cylinders. You could have leaking O-Rings on one or more cylinder sleeves. As said above you can get a overhaul kit for around $700 - 800.

SimS

 

[KubotaSteve]

Bob, you mentioned machine work. What machine work are you referring to. Is that if the head or block are warped and require milling? I just want to make sure I'm not missing anything.