[seventythree]

When mechanics start playing a high $ cost guessing game at the owner's expense, they will never admit that they simply guessed wrong. It will always come across as, well that other item needed to be fixed anyhow. That's exactly why I stopped taking my cars to mechanic shops 20 years ago. Ever since, the only time any of my cars have been to a shop was for a smog check.

Now, what is the likelihood of you having a blown head gasket, an internal leak in your oil cooler, and a bad coolant reservoir all at once?

Even with the head gasket idea, they are still guessing.

Drain the coolant and pressurize the cooling system. Keep the pressure under 15psi. Get a mechanic's stethoscope and listen through the oil filler neck. You should hear air hissing or oil bubbling if there is a head gasket leak. Try to narrow it down from there.

Bottom line, a head gasket repair will require and engine drop and partial teardown; very expensive guess work by any measure.