The first problem I see is when soldering wires. The solder flow or lack of it tells you if the joint is going to be cold or not.

Old electrical wires in cars are not always in good shape for connecting. An application of glue may mask what you might see otherwise. Plus how long is a glue based compound going to last?

You could very easily construct a high resitance point from it. I see mo advantage. Even a solder joint should be mechanically connected prior to soldering.