Pontiac Repair: 97 Pontiac Trans Sport, blown head gasket, pontiac trans sport

Question
My van started overheating and losing coolant (not sure which came first).  I kept filling the radiator to buy time for a diagnosis and repair, but, before I could get to either, something failed while my wife was driving, spewing oil mixed w/ coolant all over the driver's side of the engine compartment.  I had it towed to a mechanic. They "checked" if over and determined I would be crazy to fix it without actually diagnosing the problem.  Question:  What kind of failure would actually allow oil to be blown out of the engine and into the engine compartment?  Given the amount of coolant in the oil, I assume that I have a blown head gasket and/or cracked head.  What else should I be concerned about?

Answer
Hi Johnathan:

Well I think the root cause to this was a laking lower intake manifold gasket and the coolant was leaking into the crank case which is NEVER good the oil and coolant intermix and then the oil looses it's lubricating properties and actually starts to damage the meatal parts and bearing in the engine. the fact that it started to overheat more of less did in one or both of the head gaskets or even the cylinder heads if it got hot enough. The compression gases may have leaked into the cooling system and cause the radiator cap to release the pressure and blow the coolant all over inside the engine compartment or a hose let go due to the extra pressure in the system... Just a hunch as to the chain of events here. This van is going to be 13 years old and if it has a lot of miles on it like near or over 100K then junk the van it's not worth the price of an engine repair or replacement. Cut your losses and see what you can get as a trade in on this one.. Sorryto be the guy with the bad news :(

Good luck :)