If oil can get into antifreeze. Antifreeze can get into oil and demolish every bearing and bushing in the engine. After shut down water pressure continues till total cool down and FCA wonders why there rod bearings and crankshaft is failing this is diesel 101 big Cummins engines should have...
If oil gets into water, after 45 psi antifreeze will get into oil and cause rod bearing wear and engine failure. Water pressure stays up after oil pressure stops 15-20 psi for a long time and water is thinner than oil