The advice you have been given sofar sounds good to me, so I'll just address you question about the capillary tube giving up the ghost when the engine overheats. I twice managed to overheat B16s to the point where the paint on them turned brown-gray in spots. In both instances, I had to replace the temperature gauge, not because the tube was damaged, but rather because the return spring in the gauge itself had been over extended and the gauges would not return all the way to their normal, cold position. BTW, the engines didn't appear to have suffered any damage. I owned the first one for another six months after the incident, and during that time it didn't lose power, didn't become noisier, and didn't burn more oil. I owned the second one for another 15 years and had the engine rebuilt about 100k miles after the incident - not so much because it needed it, but because I was moving away from a really good mechanic whom I trusted to do the job right.
Bob S.