Engine coolant leaking internally and/or externally.
Any internal coolant leak can cause a milky residue in the valve cover. Head gasket, intake gasket, cracked/warped head, cracked intake are possible causes.
Repairing intake gasket not preferred, you can use red silicone to seal it, but to do so, you must remove the intake, in which case, you may as well replace the gasket.
a bad head gasket or intake manifold gasket.
arm & a leg
no. you might have ran it hotand cracked it that way.
A cracked/warped head, Blown head gasket, cracked cylinder wall, or cracked/warped intake manifold.
intake manifold gasket,head gasket,cracked head,cracked block. was it overheated? was cold water added to hot engine?
you have a broken head gasket or cracked head.
I had that happen once. That's a bad thing. That's either cracked head, blown head gasket, or cracked block.Not necessarily. The intake on some vehicles, especially late models, the coolant circulates thru the intake manifold. You could have a leaking hose or leaking manifold gasket. You would have other problems like cooant in the oil or oil in the coolant if you had a cracked head/block or a bad head gasket.
Let's see...cracked head, cracked head gasket, cracked intake gasket, bad cylinder liner or cracked block, air compressor head gasket...if this was a Cat 3116 I'd also look at the oil cooler or an injector sleeve, but it's not so that's probably not it.
Blown head gasket, cracked head, failed intake manifold, etc
Neither 1, It is a common problem with that engine for the intake gasket to leak engine coolant into the engine lifter gallery / into engine oil. Replace intake manifold gasket and change oil and FILTER a couple of times. A head gasket or cracked head will not allow engine coolant to get into the oil. If you got or over HEATED the engine like real hot then you may have blown are cracked a head but I doute it. Not common, Replace intake gasket and you'll see that the engine will be okay more then likely.