It started with overheating a few times, then, upon noticing the yellow buildup on the thermostat, thought that I had a bad head gasket. Overheating would blow all the coolant out the overflow.

Took it to mechanic #1. Said I was right, probably a head gasket. Removed head, inspected gasket - told me the gasket looked fine, probably the head. He gave me a price on checking the heads... close to $200 a piece. Told me replacement castings (JE06) would run $800 a piece. I explored alternatives and discovered were the part store gets their castings and that they also sell to public. What was even better was they sell the complete head for $286 including shipping. I asked the mechanic about his willingness to slap on heads that I purchsed, he said no prob. I asked if we still should test the old heads or just buy two new ones for a little more. He said that testing the heads would tell you if you had a crack in the block, but he's never seen it and the odds would be 99.999% that it would not be the block. I trusted his synopsis and we completed the rebuild with new gaskets and heads.

Well, guess what........

Still overheating, and took it to another mechanic who confirmed the presence of compression gasses. however, a leakdown test revealed two cylinders leaking, on separate heads, diagional across from one another.

My question, is how likely is it to have a craked block in two places, allowing compression gasses in the coolant. Mechanic #2 next step isto tear intothe work of mechanic #1 and pressure test the heads.

I've got a lot of money dumped into this.... I'd hate to dump more money into a dead engine.. But with all the work and new heads, waterpump, etc done, I don't want to abandon a good vechicle for someone's error.

Ideas?