So i'm the proud, new owner of a far from perfect 1987 300TD but i think i have either a blown HG or cracked head? it is a #14 head and the ruined old fan clutch probably didn't keep the temps down. odo shows 205k. i notice little bubbles coming from the small hose on the expansion tank if i fill it up high enough to submerge it. also abnormal pressure i think. is this hose supposed to be flowing hot coolant? is the radiator blocked forcing it to go through this or something? it really moves when revved. the engine temp doesn't move off 80c and runs great! i think i noticed a thin layer of soot or something floating in the coolant after it sitting overnight. can i tell if its a crack or blown HG without removing the head? what if i keep driving it until i can fix it? doesn't lose coolant, hoses don't have a ton of pressure but still have pressure. where can i get a later head when i'm ready? about how much will it cost? i was really thinking about doing the job myself. am i crazy? ill post pics of the wagon later! here is clip of the bubbles:

[url]https://www.youtube.com/watch?

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83 300CD- sanden, dual p/f condensers, 160a alternator, ect
91 300TD- 722.6, #22 head, 3.5L IP, w140 manifolds, ect