I'm in the process of trying to remove the exhaust elbow on my Westerbeke 21. Forgetabout trying to unscrew the elbow itself, never happen. The elbow mounts on a small flange that bolts to the block with 3 bolts. Murphy's Law says if you have 3 bolts, two will come off without any problems, but the third....forgetabout it! I've gotten the nut off the 3rd bolt but apparently the flange is frozen to the bolt with corrosion. With the other 2 bolts off the flnage is loose. I've tried WD40. I tried applying heat. Last night I bought PB Blaster and soaked it. Does anyone have any ideas for releasing a frozen bolt?