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.

 

[adventure bob]

The minimum machine work depends on some of the testing you've already had done: I'm assuming you had it magnafluxed and/or pressure tested? Howd the results go? If there are no issues with the head and its flat at the deck, you may get away with doing nothing to the head. If it pressure tested fine at the valves and you were on a tight budget Id leave them alone. Ooops more later computer is applying an update.

 

[adventure bob]

You haven't said if they found a leak in the head so I'm assuming you still don't know why you had the original issue.
If the valves or stem seals leaked, Id replace the valves and have them do the machine work for that and replace the valve seals.
Some of the machining on the block would be based on a diagnosis from: hot tank, pressure check and magnaflux for cracks.
If there's no issues in the block you can choose how much "freshening" you want to do. New bearings? deck the block? New sleeves?
As in my original response, finding nothing wrong isn't really helpful in diagnosing your original issue though.

 

[KubotaSteve]

I'm still waiting on the results from the head. They had hoped to get to it this week but I haven't heard anything yet. I'm gonna clean the valves up some. I didn't take the block out as I have no way to handle it due to weight. I'm still leaning towards the head gasket being the issue. If I get a good report on the head, I'm gonna put it all back together and see how it does. If it happens again, I may have to have someone come and get it to work on it at their shop

 

[adventure bob]

You may want to take get a machinist rule and check the block. It wont be totally accurate but you can get close enough. Run it corner to corner and try to slip a feeler gauge under it. If it seems pretty flat then it may be ok. You haven't unbolted the crank or any of the internals yet have you?

 

[melli]

Did you do a compression test before you pulled the head?
I second Adventure Bob's suggestion. I'd also get some light on block and look for hairline cracks on top of block, especially around bores.
I had an engine blow up this way (coolant in oil). New head gasket masked symptoms for a few days, then I really cracked block....lol
Didn't need a light the second time around...

 

[KubotaSteve]

I took the oil pan off today and looked up inside. I didn't see anything out of the ordinary. I looked the block over top and bottom and I didn't see anything. I was actually looking at the real precision straight edges online.
I haven't taken anything off the internals as they all look good. Still no word on the head yet.
The reason I'm leaning towards head gasket is that the head bolts seemed a lot tighter than the specs. I'm thinking someone replaced it and overtightened it.
I didn't do a compression check before pulling head. I realize now that I should have done that first but hind sight is always 20/20

 

[adventure bob]

How do the cylinders look for wear and tear? Do you see any evidence of blow by from the bottom end? any weird wear patterns in the cylinders?

 

[KubotaSteve]

Everything looked fine to me, but to be on the safe side I'm having a mechanic come by and take a look at it either today or tomorrow. He wants to check the bearings as well to make sure they aren't hurt. He also mentioned pulling the water pump off and looking at it as well. Depending on his advice and the results of the head tests will tell me what my next move will be. If all is well, I hope to have it back together in the next week or so.

 

[KubotaSteve]

Well I got the head back today and it was good for the most part. They did resurface the head and cleaned it real good. picked up new gasket set and getting ready to reassemble it. I've already got the head put back together. John Deere dealer did not have all the head bolts in stock, but I'll have them Monday. Also found a bypass hose on water pump that needed replacing as it is a molded hose and someone replaced with cheap hose that was pinched off.
Any other tips or suggestions putting it back together.

 

[adventure bob]

Proper torque and torque lube, like ARP Utlra Torque. You can get it at most auto parts stores. Did they test the valves and valve seals for leakage?