Driving home from the junkyard yesterday after scoring cheap Geo Metro parts and my original 1983 120k mile 4d55 made some funky high pressure hydraulic noises and started blowing massive coolant out the reservoir which promptly vaporized on the exhaust and turned me into a freak show of swirling white-gray smoke, much to the dismay of many Santa Cruzians around me. Power dropped off hugely, wouldn't idle without goosing the throttle. While limping into a parking lot, noticed lots of smoke while accelerating which disappeared on snap off throttle and coast.

Rad cap seems healthy, just doin it's job. Overall coolant level didn't drop much, recently topped off. Been dramatically down on power for months now, figured ring seal was shot. Relatively new turbo, shouldn't be the problem. No visible engine leaks or rad leaks. No diagnostics yet, but sure does feel like a rotted head gasket (oem, never touched)

Any thoughts out there before I tear into it?