[shorod]

If the vehicle experiences or has experienced primarily short trips, the foamy stuff in the oil fill cap is not necessarily abnormal. It could just be due to the engine rarely getting warm enough for long periods to fully evaporate all moisture out of the oil. Also, on cool mornings with a cold engine it's not abnormal to see what appears to be water/smoke from the tail pipe. The catalytic converter converts unburned fuel to water vapor. This water vapor can settle in the exhaust. When the cold engine is started, this water vapor burns off and can cause people to suspect head gaskets if they are not used to seeing this.

As for the charging system voltage concerns, I'd suggest you remove the cables from the battery, clean them well, reconnect them and make sure they are tight. Then continue to monitor the charging system voltages. You might pick up one of the inexpensive 3-LED monitors that just plug in to one of the lighter sockets. Ask your wife to pay attention to if the LEDs drop to the yellow or red when idling at stops lights, etc.

-Rod