It will be interesting to see how long the chemical lasts. My Old Trol has had chemiweld fix done almost 18months ago, to stop the radiator weeping. My Brother in law ran his Honda civic for three or four years when the head gasket leaked and he gave it a shot of chemical assistance. Since your engine is on its way out, I reckon you should drive it till it drops, and run a pool on how many ks you get out of it.