Concise description of your best mechanical trouble

[davepl]

I'll give two examples, and of course, ones that might help people in the future are better. Only my second one meets that criteria.

In my '69 2+2 (call it an Impala SS427) I was driving cross-country and the battery kept overheating to where the sides were squishy. I stopped at a couple of shops along the way who confirmed the charging voltage was good, battery and alternator, and so on. Everything was perfect but it persisted.

It turns out I had one of those old Carter fuel pumps (the ones the 'click' instead of whir, and come on only when pressure drops). I think what happened is that the fuel pump would 'click' on for 1/4 second or however long, draw some decent amps, which would click on the regulator. If the regulator relay took longer to turn back off than the pump ran for, it'd charge longer than the draw persisted, thereby overcharging.

Ultimately I solved it by driving with my headlights on (this was early 80s before that was common). Later, I ditched the pump which solved it permanently.