Some funny smell from 225 (coolant)

Never jump to the conclusion "bad head gasket". Many unscrupulous mechanics will purposely put that thought in a customer's head, without a full investigation, then the customer runs with it. A co-worker asked me about losing coolant in his Chevy truck w/ LS engine, after a mechanic gave that "head gasket" speech. I asked if he smelled coolant in the cab in winter. Yes, he did. I suggested "leaking heater core". Instead of checking that, he started searching for another truck to swap the engine, then ended selling his truck. He was an engineer (but EE). A gomer shop tried that on my sister in 1970's with her 1967 Mustang straight-six on a long drive. I told her to keep driving (17 then, but knew a little) and found a busy shop further down which found a pinhole leak in a heater hose (so tiny the spray was evaporating and not leaving a noticeable liquid) and fixed it for $5.