P&H crane oil/coolant mix after radiator swap

[Hoist.And.Haul_2000]

I replaced the radiator on my P&H crane a few weeks ago, and now I'm noticing oil and coolant are mixing. Could it be that a pressure imbalance in the cooling system is to blame? I'm looking for some checks to verify before I start investigating further.

 

[Blaqshades73]

Probably a blown head gasket, cracked head, or a faulty oil cooler rather than just a pressure imbalance. Check for white smoke or milky oil