Gray Oil

ScottJI · Dec 24, 2015

Help? Hello, I have a 1981 Case 580C Backhoe that has gray colored oil. Further, when I pull the oil pan plug I get app. 1 quart of anti-freeze after idling 15 to 20 minutes. I pulled the head to replace the head gasket. I could not see any visible cracks so I replaced all necessary gaskets. It did not fix the problem of anti-freeze in the oil and the oil being gray colored when checked with the dip stick. Is there anyway to tell if it's the head or the block that is possibly cracked or could it be something else? I would greatly appreciate any advise regarding this problem and/or diagnoses. Thanks!

stan33 · Dec 24, 2015

What was the state of the gasket when you took it out?
If you had a crack they aren't always visible to the eye, so heads usually get sent for testing, then get a skim.
On my Perkins, there is a common issue where a liner slips slightly which can be almost undetectable by eye, but enough to give the impression that it's the gasket when in fact it's a liner....not sure if it could apply in your case.
Did it overheat, if so did you check the thermostat, the water pump, rad, fan belt?

GManBart · Dec 25, 2015

It's possible to have cracks in a head that you can't see....they don't open up until the head heats up as the engine runs.

Is there oil in the coolant as well? Is the engine smoking...white/gray smoke?

Gray oil/sludge is evidence that water is getting to the oil, further confirmed by the obvious coolant in the oil.

What did the tops of the pistons look like when you pulled the head? Where any a different color from the other, and were any of them light-colored rather than typical black carbon deposits?

If the head was cracked you'd be more likely to see (but not always) coolant getting dumped out the radiator overflow, a hard/swollen upper radiator hose, etc (the cooling system is getting pressurized through the head).

I'd say the most likely culprit is a cracked block. Also, coolant in the oil will wipe out the camshaft and crankshaft bearings very, very quickly, so you might already be to the point of needing to pull the engine apart anyway.

Coyote machine · Dec 25, 2015

Welcome to TBN.
Replacing a head gasket, at how many hours on the machine? What led up to the need to pull the head? Since you'll have to do the teardown again, this time have the head checked by a good quality machine shop. You'll have to determine if there is block or cylinder liner damage too, especially if the head tests good with no cracks, etc.
1981 is an old machine; how long have you owned it, and how much and what kind of use does it see from your working it?
Are there any known problems with this vintage and model machine that you are aware of?
Post back answers....

ScottJI · Dec 25, 2015

Yes it did overheat. I was operating the hoe part so I couldn't monitor my gauges until it was too late but I didn't think it overheated that bad. The water pump, belt and pulley were good, however I suspect the thermostat was not working like it should. It was obvious that there was traces of oil and anti-freeze on the old gasket but it didn't appear like it went as far in as to reach the cylinders or ports. After replacing all the gaskets and put back together I still have the same problem of grey looking oil, pure anti-freeze in the oil pan and after just a short time, the oil level according to the dip stick had gained to way over full. I was hoping there was a way for me to tell if it is the block or the head without sending the head in first in case it's the block and not the head. Is there anyway to do that?

2458n · Dec 25, 2015

Check to see if head is level. Liners all need the same height. You know the oil and water are mixing, start checking the cost for getting another engine.

Tx Jim · Dec 25, 2015

I think you should level of cyl head checked and it magnafluxed for cracks. Does 580 engine have an engine oil cooler? If so it could be leaking. It's also a possibility for electrolysis to have made a hole in a cylinder wall.

Billrog · Dec 25, 2015

You will most likely have to pull the liners and replace the O rings . I hope you haven't damaged the crank.

LarJea · Dec 25, 2015

Aside from pulling the liners and replacing the O-rings and making sure the liners still fit tight. The liners could be damaged by erosion from cavitation of the coolant and have caused pin holes in the liner. I always used a coolant additive specifically designed to stop cavitation from happening in my 580B.

Stimw · Dec 25, 2015

The oil turns gray from the detergent in the oil.
As stated, check oil cooler but with an overheat it will be a bigger problem.
It doesn't take much for some heads to warp or crack. Ford 172 cu in gas are known for it as an example. I have seen over 6 of them myself! Had 1 welded, had to junk the rest.